AP Chemistry: Chapter 2 - Atoms, Molecules, Ions

7/27/2019 AP Chemistry: Chapter 2 - Atoms, Molecules, Ions

1/17

AP Chemistry

To: 2013-2014 AP Chemistry studentsFrom: Big Evergreen III, a past student of Mrs. Moses

SUBJECT: Hints / strategies / review to survive AP Chemistry.

Think categorically: know acid from base, strong from weak, metal from nonmetal,ionic from covalent, etc.

Know your nomenclature, you will need it for everything. When you are taught something, learn it: many concepts are reused within other

concepts so if you didnt learn something in the first place it will hurt you later. Know your solubility rules: this will help so much on the reactions part of the exam! Learn the details and the relationships: How does temperature, pressure, etc. affect a

certain system? What does it mean if something is solid, liquid or gas?What are certainnumbers dependent upon?

Table of Contents1. Atoms, Molecules, and Ions...........................................................................................................

2. Stoichiometry.................................................................................................................................

3. Reactions ........................................................................................................................................

4. Gases ..............................................................................................................................................

5. Thermochemistry ...........................................................................................................................

6. Atomic Energies & Periodicity ......................................................................................................

7. Fundamentals of Chemical Bonding ..............................................................................................8. Theories of Chemical Bonding ......................................................................................................

9. Liquids & Solids ............................................................................................................................

10. Properties of Solutions .................................................................................................................

11. Kinetics ........................................................................................................................................

12. Chemical Equilibrium ..................................................................................................................

13. Acids and Bases ...........................................................................................................................

14. Aqueous Equilibria ......................................................................................................................15. Spontaneity of Chemical Processes .............................................................................................

16. Electrochemistry ..........................................................................................................................

17. Nuclear Chemistry & Radiochemistry .........................................................................................

18. O-Chem aka Organic Chemistry ..................................................................................................
http://i1278.photobucket.com/albums/y505/snhs1/apchemtopicoutline_zpsa9e3e000.pnghttp://i1278.photobucket.com/albums/y505/snhs1/apchemtopicoutline_zpsa9e3e000.pnghttp://i1278.photobucket.com/albums/y505/snhs1/apchemtopicoutline_zpsa9e3e000.png


2/17

Atoms, Molecules, and Ions2.1 The Atomic Theory of MatterDaltons Theory 1807

1) Elements are composed of small particles called atoms.2) Atoms of an element are identical; atoms of different elements are different.

3) Atoms cannot be created or destroyed during chemical reactions.4) Compounds are formed when atoms of different elements combine.

Law of Conservation of mass: during a chemical reaction, mass is conserved. Total mass of the reactants = Total mass of the products

Law of Multiple proportions: If 2 elements A and B combine to form more than 1

compound, the mass of B which combines with a mass of A is a ratio of small wholenumbers.

E.g. H2O and H2O2

2.2 The Discovery of the Atomic StructureElectrons

Results of Thomson's experiments (1890's) on the behavior of cathode rays inelectric & magnetic fields:

cathode rays consist of negatively charged particles called electrons charge to mass ratio of e-(electron) = 1.76 x 108 C/g

Results of Millikans oil drop experiment: charge of e- = 1.60 x 10-19 C; mass of e- = 9.11 x 10-28 g

Radioactivity: spontaneous emission of radiation

Results of Rutherford's experiments on radiation (1910-1920) An atom has a nucleus - a small, dense, positively charged region. Electrons are located outside of the nucleus. Most of the atom is empty space.

Three types of radiation exist(This is a little introduction to Nuclear Chemistry. Well talk

more about this in Chapter 17):

1. alpha: high mass particles with +2 charge (helium nuclei)

2. beta: low mass particles with -1 charge (electrons)

3. gamma: neutral, high energy radiation similar to x-rays

2.3 The Modern View of Atomic StructureNuclear Model:1) Atoms consist of protons, electrons & neutrons (3 subatomic particles).2) Protons & neutrons are located in the nucleus; it contains most of the mass.Size analogy: If an atom were the size of a football stadium, nucleus would bethe size of a marble.3) Electrons move rapidly in region outside of the nucleus.

Masses of atoms are so small that we use the atomic mass unit (amu) to scale up thenumbers. 1 amu = 1.66054 x 10-24 g


3/17

electron: -1 charge, (neglible)mass = 9.11 x 10-28 g = 5.486 x 10-4 amu, Thomson (1897)proton: +1 charge, mass = 1.672 x 10-24 g = 1.0073 amu, Rutherford (1919)neutron: no charge, mass = 1.675 x 10-24 g = 1.0087 amu, Chadwick (1932)

Isotopes

atoms of an element that have a different number of neutrons. Isotopes of an element have the same atomic number, but a different mass number. Example, 3 H isotopes:

Protium, or normal Hydrogen, = stable. Deuterium = stable. Tritium = radioactive

2.4 The Periodic Table -1st table 1869Features of modern periodic table:

1) Elements arranged in order of increasing atomic number(equal to # of protons).2) Horizontal Rows in periodic table are called periods. 7 periods exist3) Vertical Columns are groups or families; elements have similar properties.

Group names:1. Group 1A: alkali metals2. Group 2A: alkaline earth metals

3. Group 7A: halogens4. Group 8A: noble gases


4/17

4)

Metals are located to the left of the stair-step line. Nonmetals are located tothe right of the stair-step. Elements located at the stair-step are semiconductors or metalloidelements: B, Si, Ge, As, Sb, Te, At

Physical state of elements at 25 C & 1 atm(remember, this is STP, or standard temperature andpressure. Youll need to know this when we get to Gases):

Gases: O2, N2, H2, F2, Cl2, and Noble gases Liquids: Br2, Hg Solids: everything else

**This is actually really important and you might see it on the exam!

2.5 Molecules and Molecular Compounds

molecule: 2 or more atoms bonded together; discrete entities. Many elements exist as diatomic molecules(HBrINClOF): H2, N2, O2, F2, I2, Cl2, Br2

Molecular compounds consist of nonmetal elements.Molecular formulas give the actual numbers and types of atoms in a molecule.

CH4, H2O2, C2H4, C6H12O6Empirical formulas give the smallest whole number ratio of atoms in a molecule.

CH4, HO, CH2, CH2O

2.6 Ions and Ionic Compounds

Many chemical reactions involve transfer of electrons between atoms: Metal atoms tend to lose electrons & form (+) charged cations. (Im positive I hate cats) Nonmetal atoms tend to gain electrons & form (-) charged anions.

Generally, atoms gain or lose enough electrons to have same number of electrons as nearestnoble gas: (If you dont understand this, please come see me so that I can explain it to you on theperiodic table. Its a lot easier than it seems and its really helpful when you get to Bonding.)

Group 1A 2A 3A 5A 6A 7ACharge of ion 1+ 2+ 3+ 3- 2- 1-


5/17

Ionic compound: consists of metals and nonmetals (or polyatomic ions); ioniccompound is a long 3-D array of cations & anions; not individual molecules.

Formed by attraction between oppositely charged ions Are called ionic solids or salts (NaCl = a salt)

Ionic formulas: the number of electrons lost & gained must be equal, so (+) and (-)charge cancel out. (Drop-and-switch method)

Rules for writing ionic formula:1) Write down formulas of ions2) Combine the smallest # of ions to give the charge sum equal to 0; if thecharges are not equal, find the lowest common multiple

(If you dont understandplease let me know. Ill be more than willing to show it to you on paperand how simple it really is!)

Predict the formula for the compound formed from the following elements:Ca & O:

1. Find the ions/oxidation #. Ca = Ca2+ and O = O2-2. Make charge sum equal 0. Ca2+O2- CaO3. The 2- charge cancels out the 2+ charge. (-2 + 2 = 0)

Mg & N:1. Find the ions/oxidation #. Mg = Mg2+ and N = N3-2. Make charge sum equal 0. Mg2+ N3- Mg3N23. Drop & Switch: the 2+ and 3- dropped down as subscripts and then they were

switched. Mg2+ N3- to Mg2+ N3- to Mg3N2 ((3x2) + (2x-3) = 6 + -6 = 0)Al & Cl:

1. Find the ions/oxidation #. Al = Al3+ and Cl = Cl1-2. Make charge sum equal 0. Al3+ Cl1- AlCl33. Drop & Switch: the 3+ and 1- dropped down as subscripts and then they were

switched. Al3+ Cl1- to Al3+ Cl1- to AlCl3 ((1x3) + (3x-1) = 3 + -3 = 0)

Ions have a different # of electrons & protons Examples- Na+ has 11p, 12n, and 10e- Cl- has 17p, 18n, and 18e-

NOMENCLATURE- IONIC COMPOUNDSA. Naming Cations(positive ions that lose electrons):1. Fixed charge metals: Groups 1A, 2A, Al, Ag, and Zn are cations that have 1 specific charge.

Examples- Ag+ silver ion Zn2+ zinc ion Al3+ aluminum ionLi+ lithium ion Ca2+ calcium ion

2. Variable charge metals: If the metal can form more than 1 cation, the charge is indicated by aRoman numeral in parenthesis after the metal name. Most of the transition metals are variablecharge metals.

Common metals which exist in more than one positive state:o Fe2+ iron(II) Au+ gold(I) Cu+ copper(I) Fe3+ iron(III) Au3+ gold(III)

Cu2+ copper(II)3. Polyatomic Cations: consist of nonmetalsH3O

+ hydronium NH4+ ammonium (There are a whole lot more! And you need to memorize

them)

B. Naming Anions(negative ions that gain electrons):

1. monoatomic anions: change ending to -ide oxygen oxygen oxide


6/17

sulfur sulfur sulfide hydrogen hydrogen hydride

2. Polyatomic anions: most end in -ate or -ite; usually contain O (oxygen)Know polyatomic anions on handout!

a) Rule for naming oxy series anions:If you can remember the formula of the ion whose name ends with ate, youcan usually work out the formulas of the other family members as follows:

modify stem namewith: meaning examples

-ate a common form, containing oxygen chlorate, ClO3-

nitrate, NO3-

sulfate, SO42-

-ite one less oxygen than -ate form chlorite, ClO2-

sulfite, SO32-

nitrite, NO2

-

per-, -ate same charge, but contains one more oxygenthan -ate form

perchlorate, ClO4-

perbromate, BrO4-

hypo-, -ite same charge, but contains one less oxygen than

the -ite form

hypochlorite, ClO-

hypobromite, BrO-

thio- replace an O with an S thiosulfate, S2O3-

thiosulfite, S2O22-

b) If H+ is added to a polyatomic ion, write hydrogen (or bi-) in front of name.

modify stem name with: meaning examples

hydrogenorbi-

(1) captured H+ions hydrogen carbonate, HCO3

-(a.k.a. bicarbonate)

hydrogen sulfate, HSO4-(a.k.a. bisulfate)

dihydrogen (2) captured H+ions dihydrogen phosphate, H2PO4

-

NOMENCLATURE RULES

I. IONIC COMPOUNDS contain cations & anions1) Name metal cation.2) Include Roman numeral in parenthesis ONLY IF metal has variable charge. Fixedcharge metals(metals that only have 1 charge): Group 1A, 2A, Ag, Zn, and Al; others arevariable(have more than 1 charge).3) Name anion.

MgBr2 (Mg+ Br-) Mg is a metal cation with only 1

charge, so it is named first.Bromine is a monoatomic anion,so ending is changed to -ide

MagensiumBromide

Ba3N2 (Ba+ N -) Barium is a metal cation with

only 1 charge, so it is namedfirst. Nitrogen is a monoatomicanion, so the ending is changedtoide

Barium Nitride

PbS (Pb + S -) Lead is a metal cation with 2charges (4+ and 2+), so it isnamed first but with a romannumeral in parenthesis. Sulfur isa monoatomic anion, so theending is changed toide.

Lead (II) sulfide

Fe2(SO3)3 (Fe+ SO3

-) Iron is a metal cation with Iron (III) sulfite


7/17

Woah! Lets explain this a bit several charges, so it is namedfirst but with a roman numeral inparenthesis of the specificcharge. SO3

2- is actually avariation of sulfate (SO4

2-). Asyou can see, it has one lessoxygen, so it will end withite.

II. Binary Molecular Compounds: contain 2 nonmetals1) Name 1st element & use a prefix to indicate the number of atoms. Note that mono- is neverused for the first element.

Prefixesmono - 1 penta - 5 octa - 8di - 2 hexa - 6 nona - 9tri - 3 hepta - 7 deca - 10tetra - 4

2) Name 2nd element & include prefix for number of atoms3) Change ending of 2nd element toide.

N2O5 dinitrogen pentoxide ICl3 iodine trichloride tetraphosphorus hexasulfide P4S6 dibromine heptaoxide Br2O7

III. Acid: substance that yields H+ ions in aqueous solutionA. Binary Acids (Nonoxy acids): contain H & 1 nonmetal

1) Name hydrogen as hydro-.2) Name nonmetal & change ending to -ic acid.

HCl H+ = Hydro- Cl- = Chloric acid Hydrochloric AcidH3P H

+ = Hydro- P - = Phosphoric acid Hydrophosphoric AcidH2Se H

+ = Hydro- Se - = Selenic acid Hydroselenic AcidH2S H

+ = Hydro- S + = Sulfuric acid Hydrosulfuric Acid

B. Ternary Acids (Oxy Acids): contain H & polyatomic ion1) no hydro prefix2) Change ending of polyatomic ion:

-ate -ic acid-ite -ous acid

HNO3 NO3 = nitrate = nitric acid Nitric AcidH2SO3 SO3 = sulfite = sulfurous acid Sulfurous AcidHClO2 ClO2

- = chlorite = chlrorous acid Chlorous Acid


8/17

List of Polyatomic Ions to Memorize!!!

Moses will probably assign this list in a couple of weeks, but you guys get a head start! (:

Click here to get this list in a more organized format

and to also get a list of the metals with more than

one charge!!!

nitrate NO3-

nitrite NO2-

perchlorate ClO4-

chlorate ClO3-

chlorite ClO2- hypochlorite ClO - acetate C2H3O2

- orCH3COO

-1

hydroxide OH - permanganate MnO4

-

azide N3-

chromate CrO4-

dichromate Cr2O7-

sulfate SO4-

sulfite SO3-

hydrogen sulfate HSO4- hydrogen sulfite HSO3

-

thiosulfate S2O3-

thiocyanate SCN - cyanide CN - oxalate C2O4

-

carbonate CO3-

hydrogen carbonate orbicarbonate

HCO3-

silicate SiO3-

phosphate PO4

-

phosphite PO3-

hydrogen phosphate HPO4-

dihydrogen phosphate H2PO4-

arsenate AsO4-

arsenite AsO3-

borate BO3-

peroxide O2-

ammonium NH4+

hydronium H3O+

Moving on to Practice Problems
http://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/common_ions.pdf


9/17

Chapter 2

Atoms, Molecules, and Ions - MC

1. Methane and ethane are both made up of carbon and hydrogen. In methane, there are12.0 g of carbon for every 4.00 g of hydrogen, a ration of 3:1 by mass. In ethane,there are 24.0 g of carbon for every 6.00 g of hydrogen, a ratio of 4:1 by mass. Thisis a statement of the law of _________________.(a). constant composition(b). multiple proportions(c). conservation of matter(d). conservation of mass(e). octaves

2. Which statement below correctly describes the responses of alpha, beta, and gammaradiation to an electric field?(a). Both beta and gamma are deflected in the same direction, which alpha showsno response.(b). Both alpha and gamma are deflected in the same direction, while beta showsno response.(c). Both alpha and beta are deflected in the same direction, while gamma shows noresponse.(d). Alpha and beta are deflected in opposite directions, while gamma shows noresponse.(e). Only alpha is deflected, while beta and gamma show no response.

3. ______________ and _____________ reside in the atomic nucleus.(a). Protons, electrons(b). Electrons, neutrons(c). Protons, neutrons

(d). None of the above

4. 200 pm is the same as ____________.(a). 2000(b). 20(c). 200(d). 2.00

5. The atomic number indicates ___________.(a). the number of neutrons in a nucleus(b). the total number of neutrons and protons in a nucleus

(c). the number protons or electrons in a neutral atom(d). the number of atoms in 1 g of an element

6. Which pair of atoms constitutes a pair of isotopes of the same element?(a). 6

14X 714X

(b). 614X 6

12X(c). 9

17X 817X(d). 10

19X 919X


10/17

7. Elements in Group 8A are known as the ___________.(a). chalcogens(b). alkali metals(c). noble gases(d). alkaline earth metals

8. _____________ are found uncombined, as monatomic species in nature.(a). Halogens(b). Alkali metals(c). Noble gases(d). None of the above

9. When a metal and a nonmetal react, the _______ tends to lose electrons and the_____________ tends to gain electrons.(a). metal, metal(b). metal, nonmetal(c). nonmetal, metal(d). None of the above, these elements share electrons.

10. The empirical formula of a compound with molecules containing 12 carbon atoms, 14hydrogen atoms, and 6 oxygen atoms is ___________.(a). C12H14O6(b). C2H4O(c). CH2O(d). C6H7O3

11. ____________ typically form ions with a 2+ charge.(a). Transition metals(b). Halogens(c). Alkaline earth metals(d). Alkali metals

12. Magnesium reacts with a certain element to form a compound with the generalformula MgX. What would the most likely formula be for the compound formedbetween potassium and element X?(a). KX(b). K2X2(c). K2X3(d). KX3(e). None of the above

13. The charge on the manganese in the salt MnF3 is ______________.

(a). +1(b). -1(c). +3(d). -2

14. Barium forms an ion with a charge of _________.(a). +1(b). -2(c) +3(d). None of the above


11/17

15. Aluminum forms an ion with a charge of___________.(a). +2(b). -3(c). +3(d). +1

16. Iodine forms an ion with a charge of _____________.(a). -7(b). +1(c). -1(d). +2

17. Oxygen forms an ion with a charge of __________.(a). -1(b). +2(c). -3(d). -2

18. Predict the empirical formula of the ionic compound that forms from sodium andfluorine.(a). Na3F(b). Na2F(c). NaF2(d). None of the above

19. Predict the empirical formula of the ionic compound that forms from magnesium andoxygen.(a). Mg2O(b). MgO(c). MgO2(d). Mg3O2

20. The correct name for H2CO3 is _______.(a). carbonous acid(b). dihydrogencarbonate(c). carbohydrate(d). carbonic acid

21. The correct name for H2SO3 is _______.(a). sulfuric acid(b). dihydrogensulfite acid(c). hydrosulfuric acid

(d). sulfurous acid

22. The correct name for HC1O3 is _______.(a). hydrochloric acid(b). perchloric acid(c). chloric acid CHE141 Chapter 2(d). None of the above

23. The correct name for HBrO2 is _________.(a). bromic acid(b). hypobromous acid


12/17

(c). hypobromic acid(d). bromous acid

24. The correct name of the compound Na3N is __________.(a). sodium nitride(b). sodium azide(c). trisodium nitride(d) sodium (III) nitride

25. The correct formula for molybdenum(IV) hypochlorite is __________.(a). Mo(C1O3)4(b). Mo(C1O2)4(c). Mo(C1O)4(d). Mo(C1O4)4

26. The ions Ca2+ and PO43- form a salt with the formula ___________.

(a). CaPO4(b). Ca2(PO4)3(c). Ca2PO4(d). Ca3(PO4)2

27. Which one of the following is not one of the postulates of Daltons atomic theory?(a). Atoms are composed of protons, neutrons, and electrons.(b). All atoms of a given element are identical; the atoms of different elements aredifferent and have different properties.(c). Atoms of an element are not changed into different types of atoms by chemicalreactions: atoms are neither created nor destroyed in chemical reactions.(d).Compounds are formed when atoms of more than one element combine; a givencompound always has the same relative number and kind of atoms.

28. Consider the following selected postulates of Daltons atomic theory:

(i) Each element is composed of extremely small particles called atoms.(ii) Atoms are indivisible.(iii) Atoms of a given element are identical(iv) Atoms of different elements are different and have different properties.

Which of the postulates is (are) no longer valid?(a). (i) and (ii)(b). (ii) only(c). (iii) only(d). (ii) and (iii) only

29. Of the following, the smallest and lightest subatomic particle is the __________.

(a). neutron(b). proton(c). electron(d). alpha particle

30. All atoms of a given element have the same __________.(a). mass(b). number of electrons and neutrons(c). number of neutrons(d). number of protons


13/17

31. Which combination of protons, neutrons, and electrons is correct for the isotope ofcopper, 29

63Cu?(a). 29p+,34n, 29e-(b). 29p+,29n,63e-(c). 63p+,29n,63e-(d). 34p+,29n,34e-

32. Which isotope has 45 neutrons?(a). 36

80Kr(b). 2878Se(c). 35

80Br(d). 17

34Cl

33. Isotopes are atoms of the same element that have the same number of __________but differing number of ___________.(a). protons, electrons(b). neutrons, protons(c). protons, neutrons(d). electrons, protons

34. Different isotopes of a particular element contain the same number of _________.(a). electrons(b). neutrons(c). protons and neutrons(d). protons, neutrons, and electrons

35. In the periodic table, the elements are arranged in _________.(a). alphabetical order(b). order of increasing atomic number(c). order of increasing metallic properties(d). order of increasing neutron content

36. Elements __________ exhibit similar physical and chemical properties.(a). with similar chemical symbols(b). with similar atomic masses(c). in the same period of the periodic table(d). in the same group of the periodic table

37. An element in the upper right corner of the periodic table _________.(a). is either a metal or metalloid(b). is definitely a metal(c). is definitely a non-metal

(d). is either a metalloid or a non-metal

38. An element that appears in the lower left corner of a periodic table is _________.(a). either a metal or metalloid(b). definitely a metal(c). either a metalloid or a non-metal(d). definitely a non-metal


14/17

39. Which one of the following does not occur as diatomic molecules in elemental form?(a). oxygen(b). nitrogen(c). sulfur(d). hydrogen

40. A molecular formula always indicates __________.(a). how many of each atom are in a molecule(b). the simplest whole-number ratio of different atoms in a compound(c). which atoms are attached to which in a molecule(d). the isotope of each element in a compound

41. An empirical formula always indicates___________.(a). which atoms are attached to which in a molecule(b). how many of each atom are in a molecule(c). the simplest whole-number ratio of different atoms in a compound(d). the geometry of a molecule

42. The molecular formula of a compound is always ____________ the empiricalformula.(a). more complex than(b). different from(c). a whole number multiple of(d). the same as

43. There are ________ protons, ________ neutrons, and ________ electrons in 131I -.(a). 131, 53, and 54(b). 131, 53 and 52(c). 53, 78, and 54(d). 53, 131, and 52(e). 78, 53, and 72

45. Which pair of elements is most apt to form an ionic compound with each other?(a). calcium, sodium(b). barium, bromine(c). oxygen, fluorine(d). sulfur, fluorine

Answers and explanations:https://edocs.uis.edu/hbapa1/www/CHE141/Flash/pdf/Chapter2.pdf
https://edocs.uis.edu/hbapa1/www/CHE141/Flash/pdf/Chapter2.pdfhttps://edocs.uis.edu/hbapa1/www/CHE141/Flash/pdf/Chapter2.pdfhttps://edocs.uis.edu/hbapa1/www/CHE141/Flash/pdf/Chapter2.pdfhttps://edocs.uis.edu/hbapa1/www/CHE141/Flash/pdf/Chapter2.pdf


15/17

Chapter 2

Atoms, Molecules, and IonsFree Response

Mole map:https://staff.rockwood.k12.mo.us/grayted/apchemistry/Documents/HANDOUT%20Mole%20Map.pdf

1.a) What is the mass number of an iron atom with 30 neutrons?b) A nickel atom with 32 neutrons has a mass of 59.930788 amu. What is its mass in grams?c) How many protons, neutrons, and electrons are in a 64Zn atom?

2. a) Argon has three isotopes with 18, 20, and 22 neutrons, respectively. What are the massnumbers and symbols of these three isotopes?

b) Gallium has two isotopes: 69Ga and 71Ga. How many protons and neutrons are in the nucleiof each of these isotopes? If the abundance of69Ga is 60.1%, what is the abundance of71Ga?

4. Verify that the atomic weight of chlorine is 35.45, given the followinginformation:35Cl mass = 34.96885; percent abundance = 75.77%37Cl mass = 36.96590; percent abundance = 24.23%

5. a) What is the mass, in grams, of 1.5 mol of silicon?b) What amount (moles) of sulfur is represented by 454 g? How many atoms?c) What is the average mass of one sulfur atom?

6. The density of gold is 19.32 g/cm3. What is the volume (in cubic centimeters) of a piece ofgold that contains 2.6 X 1024atoms? If the piece of metal is a square with a thickness of 0.10 cm,what is the length (in centimeters) of one side of the piece?

7. Strontium has four stable isotopes. Strontium-84 has a very low natural abundance, but 86Sr,87Sr, and 88Sr are all reasonably abundant. Knowing that the atomic weight of strontium is 87.62,which of the more abundant isotopes predominates?

8. Verify that the atomic mass of magnesium is 24.31, given the followinginformation:24Mg, mass = 23.985042 amu; percent abundance = 78.99%25Mg, mass = 24.985837 amu; percent abundance = 10.00%26Mg, mass = 25.982593 amu; percent abundance = 11.01%

9. Silver has two stable isotopes, 107Ag and 109Ag. The isotopic mass of107Ag is 106.9051 andthe isotopic mass of109Ag is 108.9047. The atomic weight of Ag, from the periodic table, is107.868. Estimate the percentage of107Ag in a sample of the element.
https://staff.rockwood.k12.mo.us/grayted/apchemistry/Documents/HANDOUT%20Mole%20Map.pdfhttps://staff.rockwood.k12.mo.us/grayted/apchemistry/Documents/HANDOUT%20Mole%20Map.pdfhttps://staff.rockwood.k12.mo.us/grayted/apchemistry/Documents/HANDOUT%20Mole%20Map.pdfhttps://staff.rockwood.k12.mo.us/grayted/apchemistry/Documents/HANDOUT%20Mole%20Map.pdf


16/17

10. Calculate the mass, in grams, of the following:a) 2.5 mol of aluminumb) 1.25 X 10-8 mol of ironc) 0.015 mol of calciumd) 653 mol of neon

11. Calculate the amount (in moles) represented by each of the following:a) 127.08 g of Cub) 0.012 g of lithiumc) 5.0 mg of americiumd) 6.75 g of Al

12. You are given 1.0-g samples of He, Fe, Li, Si, and C. Which sample contains thelargest number of atoms? Which contains the smallest?

13. Select answers to the questions listed below from the following list of elements:C, Ca, Cr, Co, Cd, Cl, Cs, Ce, Cm, Cu, and Cf. (You should expect to use somesymbols more than once.)a) Which are nonmetals?b) Which are main group elements?c) Which are lanthanides?d) Which are transition elements?e) Which are actinides?f) Which are gases?

14. Fill in the blanks in the table:Symbol Ni S

Number ofprotons

10

Number ofneutrons

10 30

Number ofelectrons inneutral atom

25

Name of element

Questions from:http://classroom.nbisd.org/webs/kbowen/upload/atoms_ions_mol.pdfIll post an answer key with worked out problems here:http://erhsnhs.tumblr.com/tagged/chapter2

Chapter 1 Qwizdom (this looks like a lot of fun and it is a gr8 review!)http://barronchem.com/APUNITS/aphelpsheets/qwizdomchapter123.pdf
http://classroom.nbisd.org/webs/kbowen/upload/atoms_ions_mol.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/atoms_ions_mol.pdfhttp://classroom.nbisd.org/webs/kbowen/upload/atoms_ions_mol.pdfhttp://erhsnhs.tumblr.com/tagged/chapter2http://erhsnhs.tumblr.com/tagged/chapter2http://erhsnhs.tumblr.com/tagged/chapter2http://barronchem.com/APUNITS/aphelpsheets/qwizdomchapter123.pdfhttp://barronchem.com/APUNITS/aphelpsheets/qwizdomchapter123.pdfhttp://barronchem.com/APUNITS/aphelpsheets/qwizdomchapter123.pdfhttp://erhsnhs.tumblr.com/tagged/chapter2http://classroom.nbisd.org/webs/kbowen/upload/atoms_ions_mol.pdf


17/17

Chapter 2

NomenclatureA. Write the correct formula:

1. iron (III) sulfide2. silver dichromate3. sodium phosphide4. cobalt (III) nitrite

5. tin(IV) perchlorate6. diphosphorus pentasulfide7. calcium phosphite8. magnesium permanganate9. chlorous acid10. hydrosulfuric acid

B. Write the correct name:

1. S4O82. AlH3

3. Cr(SCN)34. PbO25. HBr(aq)6. Zn(HSO4)27. MnC2O48. NH4C2H3O29. H2CO3(aq)10. Fe(BrO)2

Answers here:http://web.gccaz.edu/~ldiebolt/chm151/ch2.pdf
http://web.gccaz.edu/~ldiebolt/chm151/ch2.pdfhttp://web.gccaz.edu/~ldiebolt/chm151/ch2.pdfhttp://web.gccaz.edu/~ldiebolt/chm151/ch2.pdfhttp://web.gccaz.edu/~ldiebolt/chm151/ch2.pdf