History of our understanding of Atomic Structure:



Basic Chemical DefinitionsChemists make a distinction between substances and mixtures.Substance – pure, containing only one type of particle. A particle could be an element or a compound.Element – one type of atomCompound – one type of molecule or crystalMixture – contains 2 or more types of particles that have not been chemically combinedMixtures fall into two categories based on the distribution of particles:Hetero means different.Homo means same.Heterogeneous mixture- a mixture in which there is an uneven distribution of materials sand in watertossed saladoil in waterHomogeneous mixture – a mixture in which all of the particles are evenly distributed One example is salt waterSoluble means able to dissolveInsoluble means not able to dissolveHomogeneous mixtures are commonly referred to as solutions. In a solution one type of particle spreads out to fill the spaces between the particles of a second substance.A homogeneous mixture has a solute and a solventSolute – substance that is being dissolvedSolvent – substance that is used to dissolve a second substanceMost common solvents are water and alcohol.In salt water salt is the solute and water is the solvent1524016510History of our understanding of Atomic Structure:Greek Philosophers:460 – 380 BC Democritus: He came to the conclusion that matter could not be divided up into smaller and smaller pieces forever. Eventually the smallest possible piece would be obtained, he called this particle the atom. The word atom comes from the Greek word atomos which means “not to be cut or indivisible”.384 – 322 BC Aristotle:459105040005All things are made up of 4 elements, earth, air, fire and water. The proportions of these elements present determines something’s properties.The followers of Democritus, called the Atomists, debated Aristotle and lost the debate resulting in the acceptance of Aristotle’s ideas for the next 2000 years.Development of Scientific Concepts1766 – 1844 John Dalton: Was an English chemist who based on experimentation and a review of the scientific findings of the time came up with a new concept of the atom, based on 4 atomic laws:All elements are composed of atoms. Atoms are indivisible and indestructible particles. (He gave credit to Democritus for this idea.)There are as many different kinds of atoms as there are elements. Atoms of the same element are exactly alike. Atoms of different elements are pounds are formed by the joining of atoms of two or more elements. The smallest particle of a compound is called a molecule.Chemical changes involve whole atoms or groups of atoms, but never fractions of atoms.Dalton’s model became the foundation of modern chemistry but eventually modifications were required.1897 – Joseph J. Thomson 380746013970The first to show atoms were made of smaller particles. He was responsible for finding the electron (negative charge).He described the already known neutral atom to be a pudding-like positively charged material throughout which negatively charged electrons were scattered, like plum-pudding with raisins. 1903 – Ernest Rutherford:434657557785Ernest Rutherford, English physicist in 1908. While conducting an experiment involving firing a stream of tiny positively charged particles at a thin sheet of gold foil, he discovered most of his positively charged “bullets” passed right through the gold. How could this be the case if there were a lot of scattered protons? (only a few bounced back, straight back). He realized the atom’s positive charged particles were contained in the nucleus. The negatively charged electrons were scattered outside the nucleus at the atom’s edge. (Discovered protons)1913 - Niels Bohr: -8445557785Electrons move in definite orbits around the nucleus, much like planets circle the sun. These orbits, or energy levels, are located at certain distances from the nucleus.Each orbit has a limited number of electrons that can occupy that orbit. These limits are:1st orbit = 2 e- 2nd orbit = 8 e- 3rd orbit = 18 e- 4th orbit = 32 e- 5th orbit = 32 e- 6th orbit = 18 e-7th orbit = 8 e-With a special additional limit that no outer most orbit can hold more than 8 e-.1932 – James ChadwickDiscovered neutrons.Atomic Model (Bohr-Rutherford Model) as of 1932:Quantum Theory (Electron Cloud Theory)Based on their energy and on probability electrons occupy a cloud-like region about the nucleus in which they will most likelyReview: History of Atomic StructureMatch_______ Discovered atoms had a nucleus and electrons went around it._______ Model that says electrons move in “clouds” around nucleus_______ Came up with theory of a “smallest” particle and called it an “atom_______ Thomson’s model of an atom being like a positively charged squish jelly with negative electrons floating around inside it like raisons _______ An atom can have no more that eight of these_______ Believed there were only four true elements: fire, water, earth, and air._______ Discovered electrons moved around nucleus in “orbitals.”_______Greek word that means you can’t cut or divide it any further_______ James Chadwick discovered these in 1932_______ Atoms of the same _____________ are alike_______ Created by the joining of more than one element_______ The smallest part of a compoundAtomMoleculeValence electronsNeutronsCompoundElementPlum Pudding ModelQuantum TheoryDemocritus, 400 BCRutherford, 1903Bohr, 1913Aristotle, 350 BCAtomic Structure4663440-676275What are the three main subatomic particles? Proton, neutron, electron 99.9% of atomic mass is in nucleus.Protons:positively charged particles in nucleus The mass of a proton is 1 amu. (atomic mass unit)# of protons never changes. All atoms of the same element have the same # of protons.Neutrons: found in the nucleus of the atomneutral in charge. slightly more mass than protons but considered to have a mass of 1amu. Electrons: a negative charge. located outside the nucleusEach level has different amounts of energy Electrons with lowest energy level are closest to the nucleus. Mass of an electron is 1/1836 amu Atomic Number: The number of protons in the nucleus Determines what the element is. i.e- an atom of carbon has 6 protons in its nucleus. Find the atomic numbers on a periodic table. Found on the bottom left cornerIsotopes: atoms of the same element with same number of protons but different numbers of neutronsThe atomic number is same for isotopes of an element.Atomic Mass: the sum of the protons and neutrons in nucleus. average mass of all the isotopes of that element it is usually not a whole number, because it is an ave. For example, the atomic mass of carbon is 12.011. Found in upper left corner, usually a decimalThe Atoms Family Song1st Verse:They’re tiny and they’re teeny,Much smaller than a beany,They never can be seeny,The Atoms Family.Chorus2nd Verse:Together they make gases,And liquids like molasses,And all the solid masses,The Atoms FamilyChorus3rd Verse:Neutrons can be found,Where protons hang around;Electrons they surroundThe Atoms Family.ChorusChorus:They are so small. (Snap, snap)They’re round like a ball. (Snap, snap)They make up the air.They’re everywhere.Can’t see them at all. (Snap, snap)ParticleChargeMass (in amu’s)Symbol including chargeLocation in atomOtherprotonelectronneutronReview: History of Atomic StructureBased on your reading, fill out the chart belowWhat does amu stand for? __________________________________________Using the Bohr-Rutherford model, draw a picture of an atom with 3 protons, 2 neutrons, and 3 electrons.Looking at the periodic table of elements, can you guess what element you drew? _________________________Isotopes & SymbolsTwo DefinitionsAtoms whose nuclei contain the same # of protons, but a different # of neutronsAtoms with the same atomic number, but different mass numbers.457581069215Example: Hydrogen – 11 p+ 0 no Atomic Number = 1, Mass Number = 1Hydrogen – 21 p+ 1 no Atomic Number = 1, Mass Number = 2Hydrogen – 31 p+ 2 no Atomic Number = 1, Mass Number = 3All are isotopes of Hydrogen. The number following the name is the Mass Number for the isotope.Differences in mass have little effect on an atom’s chemical and physical properties. However, different isotopes will have very different nuclear properties.Example:Uranium – 235 when hit by a neutron splits to form Krypton, Barium and 3 neutrons while releasing large amounts of energy.Uranium – 238 when hit by a neutron absorbs the neutron to become Uranium – 239.Isotopic Symbol- Isotopic symbols are a shorthand way to tell the mass number and atomic number of one atom of an element.Basic Format:Example 1:Example 2:#p+ = 23, #n0 = 28Atomic # = 23, Mass # = 51, #e- = 23, Element is VanadiumIsotopic Symbol is Steps to Drawing Atoms:Example 1: 12H55333901123951.Draw a circle to represent the nucleus 5458460412752.Enter the number of protons and neutrons into the nucleus 53327301028703.Draw a circle to represent each orbit needed around the nucleus (the number of orbits needed is equal to the number of the row the element being drawn is in on the Periodic Table)5299075685804.Enter the electrons on each orbit starting from the orbit closest to the nucleus and working out from there. Be careful to obey Bohr’s limits while adding electrons. (2, 8, 18, Max. 8 in the outer)Example 2: 2914SiStep 1: Step 2: Step 3: Finished model: or Drawing Atoms Worksheet #1For each atom below list the Atomic Number, Mass Number, # p+, # e-, and #no. Then draw a Bohr-Rutherford Model of each atom.1)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______2)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______3)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______4)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______5)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______6)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______7)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______8)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______9)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______10)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______11)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______12)Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______Drawing Atoms Worksheet #2For each atom below write its Isotopic Symbol and name. Draw a Bohr-Rutherford Model of each atom.1)13 p+, 14 no2)19 p+, 19 no3)5 p+, 6 no4)6 p+, 8 no5)1 p+, 2 no6)13 p+, 15 no7)2 p+, 2 no8)20 p+, 20 no9)9 p+, 10 no10)18 p+, 21 no11)19 p+, 22 no12)3 p+, 4 noDrawing Atoms Worksheet #3For each atom below write its Isotopic Symbol and name. Draw a Bohr-Rutherford Model of each atom.1)15 p+, 19 no2)16 p+, 13 no3)15 p+, 20 no4)4 p+, 6 no5)17 p+, 23 no6)10 p+, 7 no7)18 p+, 20 no8)5 p+, 6 no9)20 p+, 19 no10)3 p+, 2 no11)12 p+, 13 no12)20 p+, 21 noIsotopes Worksheet #1List the Name, Atomic Number (# of protons), & Mass Number, for each of the following atoms.1) 73 Ge2) 118 Sn 32 503) 30 Si4) 190 Os 14 765) 24 Na6) 89 Y 11 397) 15 N 8) 184 W 7 749) 126 I10) 173 Yb 53 7011) 57 Fe12) 174 Lu 26 71Isotopes Worksheet #2Write an isotopic symbol for the atoms described below. Name the element.1) 39 no, 33 p+2) 136 no, 86 p+3) 61 no, 47 p+4) 28 no, 23 p+5) 149 no, 79 p+6) 42 n no o, 33 p+7) 8 no, 9 p+8) 5 no, 4 p+9) 21 no, 18 p+10) 30 no, 27 p+11) 111 no, 75 p+12) 120 no, 80 p+Isotopes Logic Puzzle #1Isotopes Logic Puzzle #2Ions: Normal Atom#P+ = #e- Net charge = 0Ionization is the process by which an atom becomes “charged,” either positively or negatively.The normal state of an atom is neutral due to balance of P+ and e- Ion: Charged atomAtoms like having their outer shells complete, or” filled.” They will either borrow electrons from other atoms or give away electrons to make their outer shell full. Gaining or loosing electrons make and atom into an “ion,” a charged atom. When an atom becomes an ion it is attempting to arrive at a stable electron configuration.If an atom gains electrons (e-) it becomes negatively chargedIf an atom looses electrons, it becomes positively charged. (It now has more p+ than e-)The outer shell of an atom is called the “valence shell” and electrons in the outer shell are called “valence electrons.” If there are less than four valence electrons it is easier for the atom to give away its electrons to reach a completely filled shell. If there are more than four valence electrons, it is easier for the atom to take electrons from another atom to fill its outer shell. Remember: An atom will gain or lose electrons in order to have an outermost orbit of 8 electrons!!!!Ionization Energy: Energy required to remove electronsIt takes work to lose an electron. Recall that just like north and south magnets are attracted to each other, the electrons are attracted to the protons. To lose and electron the protons and electrons have to be pulled apart. This work is called “ionization energy.”Make the connection: Remember how rubbing your feet on the carpet can create static electricity by friction? The motion energy your body provides by rubbing is used to loosen the electrons from the atoms in the carpet and they transfer into your body. Your atoms become negative ions because they have extra electrons. Remember that the movement of electrons is “electricity” or electrical energy. When the electrons move out of your body into whatever you shock, your atoms return to neutral. ReviewDraw the atom. Then circle the stable atoms. Put a star next to neutral atoms.1)13 p+, 14 no, 10 e-2)19 p+, 19 no, 18 e-3)5 p+, 6 no, 2 e-4)6 p+, 8 no, 6 e-5)1 p+, 2 no, 1 e-6)17 p+, 15 no, 18 e-Charged Atoms Directions: For each of the following, determine whether the ion is positive or negative. Write the symbol for the ion with its charge.Ex. Zinc with 28 electrons. Since: 30 - 28 = +2 Zinc is a positive ion with a symbol of Zn2+4387850203200164193203744The Periodic Table of ElementsThe History of the Periodic Table:We have been using the periodic table; now let’s take a look at how it was developed. During the 1800’s chemists were discovering many new elements and found they needed some way to organize the data they were coming up with.Jacob Berzelius: about 1800. He was Swedish. He developed the system for writing chemical symbols.2-rules: 1st letter in a symbol is always capitalized.If there is a 2nd letter it is always lower case.Dmitri Mendeleev: Russian.-Developed a table based on atomic mass-Elements placed in vertical columns-If an element’s properties didn’t fit in column, he left a space.What do you think these blanks squares represented?Henry Moseley: (1912)-used x-rays to determine atomic # and used it to refine the p. tablePERIODIC LAW:The law governing the periodic table. Mendeleev stated, “When elements are listed in order of increasing atomic #, elements with similar properties recur at regular intervals.”Periodic Table arrangement:Period: horizontal rows on the table numbered 1-7. **PERIOD # TELLS YOU HOW MANY ORBITS TO DRAW**Family or group: vertical column on table. A group contains elements with similar properties. Roman numerals show the families.**GROUP # TELLS YOU HOW MANY VALENCE ELECTRONS YOU HAVE**Three major divisions of periodic table:(There is a staircase like ladder running down right side of table) -Elements on left are metals.-Elements on right are non-metals-Elements immediately adjacent to the line dividing metals and non-metals are metalloids (except for aluminum that is a metal).Metals: Elements on left side of the Periodic Table.Usual Characteristics: form + ions by giving up electrons.be malleable - able to bend or be hammered without breakingbe ductile- able to stretch into wirebe solid at room temp (except for mercury)have luster - they are shinyconduct electricity and heatsilver colored (except for gold and copper)react with acidsreact with non-metalsthey do not react with each otherBecause of the change in their conductivity they are referred to as semiconductors and they serve as the basis of computer chips.Metalloids: Elements adjacent to the stair case like line between metals and nonmetals.Metalloids have characteristics of both metals and non-metals.Characteristics:solid at room temp.Poor conductors of electricity at low temperatureGood conductors of electricity at high temperaturesNonmetals: Elements on right side of the Periodic Table. (Not including Column 18 – the noble gases).Characteristics:Form negative ionsReact with metalsBrittleDull in appearancePoor conductors of heat and electricityDo not react with acidsReact with each otherFour Families (groups) you should know!Alkali metals- Group IAAlkaline Earth Metals- Group IIAHalogens- Group VIIBNoble gases- (inert gases). Group O.Alkali Metals: First column on the Periodic Table.500253074930Characteristics:MetalsVery soft (can be cut with a butter knife) One electron in outer most energy level (they form +1 ions by losing this electron).Low Ionization Energy and Electronegativity making it easy to remove electrons.Highly reactive (react violently with water, acids and peroxides)Reactivity increases going down the family.Form very strong bonds.Alkaline Earth Metals: Second column on periodic table.Characteristics:MetalsTwo electrons in outer shell (form +2 ions by losing both electrons)Ionization energy and electronegativity slightly higher than the alkali metalsA little less reactive than alkali metalsReactivity increases down the familyForm slightly weaker bonds than the alkali metals.Slightly harder than the alkali metalsHalogens: Next to last column on Periodic table.Characteristics:388239028575Non-metals Seven electrons in outer energy level (gain 1 electron to become –1 ions) very high ionization energy and electronegativity making it easier for them to gain electrons.Highly reactiveReactivity increases going up the familyReact with all elements on the periodic table except Helium, Neon and ArgonDo not occur as individual (unbonded atoms) in natureHalogens will form a “diatomic molecule” – a molecule made up of 2 atoms of the same element.3219450316230There are seven elements that will form diatomic molecules any time they are present in their pure form. These elements are:Hydrogen (H2)Nitrogen (N2)Oxygen (O2) Fluorine (F2)Chorine(Cl2)Bromine(Br2)Iodine(I2)Remember them with: “Harry’s brother Ike found no candy outside.”Noble gases: Last column on periodic tableNoble gases have complete outer energy levels (8 e- in their outer energy level, except Helium which has 2e- in its only energy level, remember the 1st energy level is filled with 2 e-). They wont mix with other elements easily because they’re energy levels are complete. That’s why their “Nobel” gasses- they don’t mix with “common” elements.Characteristics:Stable electron arrangement (the outer energy level is filled)Extremely high Ionization EnergyTend not to form ions Inert - tend not to take part in chemical changesVery low melting points and boiling points making them gases at room temperature.SOME REVIEW: Transition elements: or the d-block. We will not be using these in class. These elements have suborbitals that act like valence electrons and are hard to determine behaviorMost likely groups to give up electrons?Metals because they have a lower group #, it is easier to give up a few than gain a lot Most likely to gain/grab electrons?Non-metals because they are close to 8 (a full valence shell). It is easier to get a few than give up a lot.If an element gains an electron it becomes negative, if it loses one it becomes positively charged.When you turn on a light for example, you are exciting the electrons in the filament by sending an electric current through the wire. The activity of the electrons moving from shell to shell causes a release in energy seen as light and felt as heat as the electrons fall back to their positions. Periodic Table Puns #1Use your imagination and the elements in the Periodic Table to solve each pun!Example: Five cents - NickelNi1. What you do in a play _________________________ __________2. What you do to a wrinkled shirt _________________________ __________4671060673103. “Tasty” part of your mouth_________________________ __________4. Someone who likes to start fires _________________________ __________5. Superman’s weakness _________________________ __________6. Your brother or mine_________________________ __________13258803060707. Extinct_________________________ __________8. Imitation diamond _________________________ __________9. A type of flower_________________________ __________10. Las Vegas lights_________________________ __________11. Police_________________________ __________12. Golden State _________________________ __________13. Name of a goofy convict _________________________ __________14. Mr. Mony's enemy _________________________ __________15. What you do to flowers _________________________ __________16. What you did to ripped jeans _________________________ __________17. A “prize” element_________________________ __________18. A very smart person _________________________ __________19. Person from the big blue planet _________________________ __________-31623016319520. A fur seller _________________________ __________Periodic Table Puns #2Use your imagination and the elements in the Periodic Table to solve each pun!1. Not an exciting person _________________________ __________2. Thanksgiving guests _________________________ __________3. Get clean with this _________________________ __________4. Drive away in style in a ____ _________________________ __________5. Does a body good _________________________ __________6. Proud to be an _____ _________________________ __________7. Mickey’s pal _________________________ __________8. Warrior Princess _________________________ __________9. A nice guy _________________________ __________10. Someone who loves computers _________________________ __________11. The first person in a race has the ___ _________________________ __________12. E = mc2 _________________________ __________13. This man followed the yellow brick road _________________________ __________14. How to tell a secret _________________________ __________15. Monday night TV show _________________________ __________16. A phrase from Dr. Suess _________________________ __________17. What a doctor does to his patients _________________________ __________18. Part of a whole _________________________ __________19. Place for washing dishes _________________________ __________20. Drink in an Al can _________________________ __________21. Happens when you lasso a horse _________________________ __________22. What a dog does with a bone _________________________ __________23. A sinking ship _________________________ __________24. What a cloud does _________________________ __________Electron Dot Models (Lewis Structures)Def - A simple model of the atom that can be used to illustrate chemical bondingElectron dot models consist of the Chemical symbol of the element surrounded by the valence electrons.3707130149860Example: SodiumThe Bohr-Rutherford model for sodium is:5196840112395This atom has only one valence electron so the electron dot model would be Rules:5414010170180No more than 2 electron dots per sideDo not pair electron dots until there is one dot per sideTry these!Draw Lewis Dot structures around the elements. Remember to ONLY draw the electrons in the outer shell.HHeLiBeBCNOFNeNaMgAlSiPSClArKCaGaGeAsSeBrKrIonic and Covalent BondingIonic Bonds3422015147955Ionic Bond: a chemical bond due to the transfer of electrons between a metal and a non-metal and their resulting attractions.For example, common?table salt?is?sodium chloride. When?sodium?(Na) and?chlorine?(Cl) are combined, the sodium atoms each lose an?electron, (Na+), and the chlorine atoms each gain an electron (Cl?). These ions are then attracted to each other in a 1:1 ratio to form sodium chloride (NaCl).Na + Cl → Na+?+ Cl??→ NaClCovalent BondsCovalent Bond: a chemical bond due to a sharing of electrons between two non-metals. OR a non-metal and hydrogen.Neither atom wants to give up its electrons to the other, so they share. The shared electrons stay between them, forming a very strong bond. They can share one, two, or three electrons forming single, double, or triple bonds. They can also share electrons between more than 2 atoms.15240-3810Examples: F2 (this is two flourine atoms in a covalent bond) H2O (two hydrogen atoms with one oxygen atom) CH4 (this is carbon and 4 hydrogens) Diatomic molecules are covalently bonded: List the seven diatomic molecules here:Ionic and Covalent CompoundsIonic CompoundsCovalent CompoundsMade up of ions created by a transfer of electrons from a metal to a nonmetalCrystalline solidFormula indicates the ratio between the ions in the crystal.High overall attractions (all + ions attract all - ions; all - ions attract all + ions) resulting in high mp and bp and low volatility (all are solids at room temperature)Tend to be water solubleElectrolytes - substances that conduct electricity in solution (due to the presence of free ions)Made up of molecules created by the sharing of electrons by nonmetals.Molecular compounds.Formula indicates the actual number of atoms of each element in each moleculeStrong attractions between atoms within a molecule (due to overlap of valence orbits), but low attraction between molecules resulting in low mp and bp and high volatility (most are liquids or gases at room temperature)Tend to be alcohol solubleNonelectrolytes - Substances that do not conduct electricity in solution (no free ions)Electron Dot Models and BondingDetermine the formulas for the compounds formed by the following pairs of elements by drawing electron dot models showing the electron transfers.1) Lithium (1 dot) + Bromine (7 dots)2) Hydrogen (2 dots) + Oxygen (6 dots) 3) Hafnium (4 dots) + Oxygen (6 dots)4) Scandium (3 dots) + Sulfur (6 dots)5) Sodium (1 dot) + Chloride (7 dots)6) Technetium (7 dots) + Iodine (7 dots)7) Zinc (2 dots) + Phosphorus (5 dots)Chemical ReactionsLaw of Conservation of MassAcids, Bases, and Salts:Acids Acids are compounds that releases H+1 ions in solutionCharacteristics of acids:Common Acids:Hydrochloric Acid (HCl)Sulfuric Acid (H2SO4 )Lemon Juice (Citric Acid)Nitric Acid (HNO3)Vinegar (Acetic Acid)Sour taste like lemon juiceWater SolubleElectrolytes- substances that conduct electricity when in solution due to free ionsReact with metals to release H2 gasReact with carbonates to form a saltReact with metal and causes oxidationReact with bases to form a salt and water (this is called neutralization)Changes litmus paper redpH less than 7.0BasesBases are substances that release OH- (hydroxide ions) in solutionCommon Bases:Sodium Hydroxide (NaOH)Potassium Hydroxide (KOH)Ammonium Hydroxide (NH4OH)Calcium Hydroxide (Ca(OH)2)Magnesium Hydroxide (Mg(OH)2)Characteristics of bases:Bitter tasteWater SolubleSlippery to touch (i.e. soap)Emulsify fats and oils (break into drops and hold suspended in solution)ElectrolytesReact with non-metal and causes oxidationReact with calcium and magnesium compoundsReact with acids (neutralization)Changes litmus paper bluepH greater than 7.0SaltsSalts are compounds containing a metallic ion (+ ion) and an acid-radical ion (-ion)(Metallic ion is any + ion other than H+; Acid-radical ion is any –ion other than OH-)Characteristics of salts:Water SolubleSalty tasteSolid at room temperatureHigh melting pointElectrolytespH around 7.0IndicatorsIndicators are chemicals that change color in the presence of H+ or OH- ions.Indicators can be used to tell:If a substance is an acid or baseStrength of an acid or baseCommon indicators:Litmus paper: red in acid, blue in basePhenolphtalein: colorless in acid, pink in baseHydrine paper: color varies depending upon the strength of the acid or basepH ScaleAcid/base strength is measured on a scale called the ph scale. pH stands for “ % of H+” ←Acid Base→│-------------------------│-------------------------│0 7.0 14 NeutralStrength increases moving away from 7.0Review Questions(D10)(PCAPT)Which substance cannot be decomposed into simpler substances?AmmoniaAluminumMethaneMethanol (D6) A positively charged particle will:repel a negatively charged particleattract a negatively charged particleattract a positively charged run in fear from a neutral particle(D10)(PCAPT)The chemical properties of an element are determined by itsAtomic massProton numberElectron arrangementAtomic sizeD10)(PCAPT) Oxygen has an atomic number of 8. Which of the following elements would you expect to be MOST similar to oxygen in terms of its chemical properties?Nitrogen (N)Fluorine (f)Sulfur (S)Chlorine (Cl) (D10) In order for an atom to be neutral the:number of protons = the number of electronsnumber of protons = the number of neutronsnumber of electrons = the number of neutronsnumber of protons > than the number of electrons(D10) Atom A has 5 protons and 5 neutrons; atom B has 5 protons and 6 neutrons. The atoms are:isotopes of the same element.atoms of different elements.different sizesdifferent in their properties(D10)(PCAPT)What do the elements carbon, silicon, germanium and tin have in common?They are metalsThey are in the same periodThey have the same number of electronsThey have four electrons in their outer shellFor the next 3 questions refer to the drawing below.(D10) The mass number of this same atom is:A) 6B) 16C) 17D) 33(D10) This atom would have ____ valence electrons.A) 4B) 5C) 6D) 7(D10) If another isotope of this element existed with a Mass Number of 30, it would differ from the one shown in the number of which particle?protonsneutronselectronsall of the above(D10) The maximum number of electrons in the outer orbit of any atom is:A) 2B) 8C) 10D) 14(D10)(PCAPT)Nitrogen has an atomic number of 7 and an atomic mass of 14.01. Which of the following is most true of nitrogen?Each atom of nitrogen has 7 protons and 7 neutronsEach atom of nitrogen has 7 protons and 14 neutronsEach atom of nitrogen has 14 protons and 14 neutronsEach atom of nitrogen has 7 protons and 14 neutrons(D10)(PCAPT) The atomic number of iron is 26, and the atomic mass is 55.847. What do these numbers mean in regard to protons, electrons and neutrons?There are 26 each of protons and neutrons, and the rest of the mass is the result of electrons.There are 26 protons and 26 electrons. Some atoms of iron have 29 neutrons; the 0.847 shows that there is more than one isotope of iron.There are 26 protons and 29 neutrons. Each particle has an atomic mass of 1. There are 26 protons and 26 neutrons. Since neutrons have slightly more mass than protons, the mass is greater than 52.For the next 3 questions refer to the symbol drawn below. (D10) What is the mass number of the atom represented by this symbol?A) 92B) 146C) 238D) 330(D10) What is the atomic number of this atom?A) 92B) 146C) 238D) 330(D10) This symbol is referred to as a(n):Formula SymbolIsotopic SymbolAtomic SymbolIonic Symbol152400059055 (D10) In the drawing to the right, the atoms all belong to what family?Nobel GassesAlkaline EarthHalogenAlkaline Metals (D10) In order to be identified as the element carbon (C), an atom must have ______.6 protons6 neutrons12 electrons 12 electrons(D10) Oxygen has an atomic number of 8. Which of the following elements would you expect to be most similar to oxygen in terms of its chemical properties?Nitrogen (N)Fluorine (F)Sulfur (S)Chlorine (Cl)(D10) Group I (the alkali metals) includes lithium (Li), sodium (Na), and potassium (K). These elements have similar chemical properties because they have the same __________.numbers of protons and neutronsnumbers of electrons in the outer energy levelnumbers of protons in the nucleusnumbers of neutrons in the nucleus(D10) Metals and nonmetals generally form ionic bonds with each other. Which of the following sets of elements will most likely for an ionic bond?Na, FCl, FNa, KHe, O(D10) The chemical properties of an element are determined by itsatomic mass.proton number.electron arrangement.atomic size.1257300237490(D10) Study the table below. Which atom has a net positive charge?Atom WAtom XAtom YAtom Z(D10) Which element in the table above has the highest atomic mass?Atom WAtom XAtom YAtom Z(D10) Which of the following is the most important factor in determining an element’s place in the periodic table?number of protonsnumber of neutronsatomic chargeatomic density (D10). Elements in the same family all have the same:Atomic Numbersnumber of valence electronsvalence energy levelnumber of protons(D10) On the Periodic Table the elements are arranged by:Atomic NumberMass Numbernumber of neutronsnumber of isotopes(D10) An element that shows characteristics of both metals and nonmetals is:an alkaline earth metal.a noble gasa metalloid.a halogen.(D10) An element conducts electricity and heat, and has high luster. It is probably a:MetalNonmetalLiquidGas (D10)(PCAPT) The mass of an element is determined mainly by itsAtomic numberNumber of protons and neutronsElectron arrangementAtomic size (D11) Which of the following is best classified as a compound?Helium (He), because it contains only one type of atomOxygen ( O2 ), because it contains two of the same type of atomsCarbon dioxide (CO2), because it contains two different types of atomsManganese (Mn), because it contains a metal and a nonmetal(D11) In general, the force that holds atoms together in a compound is calledgravitymagnetismchemical bondelectronegativity(D11) The formation of a chemical bond involvesonly the protonselectrons & neutronsprotons & electronsonly the electrons(D11) When an atom becomes an ion it is attempting to:gain electronslose electronsshare electronsobtain a complete valence energy level(D11) To become a +3 ion, an atom must:gain 3 electronslose 3 electronsgain 3 protonslose 3 protons(D11) The chemical properties of elements are determined by the gain, loss, or sharing of:electronsionsprotonsneutrons(D11) A covalent bond would most likely be formed between Fluorine and:SodiumOxygenMagnesiumHelium(D11) A bond due to a transfer of electrons from a metal to a nonmetal is a(an):physical bondionic bondcovalent bondmetallic bond(D11) An ionic compound forms between ametal & nonmetalnonmetal and nonmetalmetalloid and nonmetalmetal & metal(D11) An atom gains two electrons to have a ___ charge.+2+4-20(D11) Two atoms that are sharing a pair of electrons have formed a(n) _______ bond.IonicJamesCovalentCooperative(D11)(PCAPT)When a metal atom combines with a nonmetal atom, the nonmetal atom willLose electrons Share electrons Grain electrons Not change its number of electrons(D11)(PCAPT)A balanced chemical equation reflects the idea that the mass of the productsis greater than the mass of the reactantsIs less than the mass of the reactantsEquals the mass of the reactantsIs not related to the mass of the reactants (D11) In a simple chemical compound the total charge must add up to:an even numberzeroan odd numbereight (D12) Which of the following has the most H+ ions present?strong acidweak acidstrong baseweak base(D12) An acid's properties are due to the presence of:Na+ ionsOH- ionsH+ ionsCl- ions(D12) A base is a compound that contains:CO32- ionsOH- ionsH+ ionsO2- ions(D12) A material, such as Cabbage Juice, that changes color in an acid, or base is called a(n):chameleonacidbaseindicator(D12) pH scale ranges from 0 to:7101420(D12) The pH that indicates the strongest acid is:0.66.37.010.5(D12) Which of the following has the most OH- ions present?strong acidweak acidstrong baseweak base(D12) The pH of a salt is around:1.47.010.214.0(D12) When an acid and base react, the resulting solution has a pH around:1.06.07.012.0(D12) The safest way to test for an acid or base is:see how it reactstasting ittouching itusing an indicatorHCl + NaHCO3 → NaCl + CO2 + H2O(D12) Antacids contain bases that react with the acid in your stomach to relieve indigestion. In the reaction above, NaHCO3 reacts with the strong hydrochloric acid, HCl, to form a salt, carbon dioxide, and water. This type of reaction is calleddehydration oxidation titrationneutralization (D12) Determine if the following are acids, bases or neutral. If the compound is an acid or base indicate if it is weak or strong. Solution A has a pH of 11.4 ________________________Solution B has a pH of 6.3 _________________________Solution C has a pH of 4.3 ________________________Solution D has a pH of 7.0 ________________________Solution E has a pH of 8.2 _________________________ (D12)(PCAPT) When an acid and a base react with each other __________and ___________are produced. Salt and CO2 Hydrogen and heatSalt and waterHeat and oxygen(D12) One property of bases is that they:are nonelectrolytesreact with metals to produce Hydrogen gastaste bitterturn litmus red(D12) A compound contains a metal and a nonmetal. The compound would be a(n):saltcovalent compoundacidbase(D12) One property of salts is that they taste:saltysweetsourbitter(D12) An indicator determines the presence of an acid, or a base by:producing bubblesgiving off an odorchanging colorburning brightlyWhich of the following is an example of a chemical reaction?Aluminum foil being cut into smaller piecesA drop of food coloring dissolving in waterMelted butter becoming a solid when placed in the refrigeratorThe surface of a copper penny changing color after being in a drawer for yearsWhich of the following?always?results from a chemical reaction?FireBubblesA new substance that is a solidA new substance that can be a solid, liquid, or gasA student placed a liquid in a jar and sealed it.? Then she heated the liquid and it turned into a gas.? If the number of atoms in the sealed jar stayed the same, what happened to the mass of the jar and everything inside it after she heated it?The mass increased.The mass decreased.The mass stayed the same.It depends on whether a chemical reaction occurred.A student places some baking soda and a jar of lemon juice in a plastic bag and seals the bag. She weighs the bag and everything in it. She shakes the bag so that the lemon juice spills out of the jar and mixes with the baking soda inside the bag. The student observes that bubbles form and the bag expands.If the student weighs the bag and everything in it after the bubbling stops and compares the final weight to the starting weight, what will she find out?The final weight will be greater than the starting weight because new atoms are produced during the experiment.The final weight will be less than the starting weight because some of the atoms are destroyed during the experiment.The final weight will be the same as the starting weight because the number of each kind of atom does not change during the experiment.The final weight will be the same as the starting weight because some atoms are destroyed, but new ones are created during the experiment.A student adds water and sugar to a jar and seals the jar so that nothing can get in or out. The student then weighs the jar containing the water and sugar. After some sugar dissolves, the student weighs the jar and its contents again.What will happen to the weight of the jar containing the water and sugar after some of the sugar dissolves?The weight will stay the same.The weight will increase.The weight will decrease.The weight will depend on how much sugar dissolves.In the diagrams below, sulfur atoms are represented by gray circles, carbon atoms are represented by black circles, and oxygen atoms are represented by white circles.Which of the following could be a product of the chemical reaction between sulfur and oxygen?Which of the following could represent a chemical reaction?Atoms are represented by circles, and molecules are represented by circles that are connected to each other. The different colored circles represent different kinds of atoms.Using the information about the five liquids in the table below, which of the following liquids could be the same substance??Volume(mL)FlammableBoiling Point(°C)ColorLiquid 125no100colorlessLiquid 250no100colorlessLiquid 325yes100colorlessLiquid 425no78colorlessLiquid 525no100yellowLiquids 1 and 2Liquids 1 and 3Liquids 1 and 4Liquids 1 and 5Which of the following is an example of a chemical reaction?Water evaporating from a pot on a hot stoveSand being removed from sea water by filtrationA spoonful of sugar dissolving in a glass of waterA white solid forming when two clear liquids are poured together ................
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