Putting it together, chapter 5 (p.125, multiple choice questions 1-15)
1. The concept of positive charges and a small “heavy” nucleus surrounded by
electrons was the contribution of (a) Dalton, (b) Rutherford (c) Thomson (d)
Chadwick.
2. The neutron was discovered in 1932 by (a) Dalton, (b) Rutherford (c) Thomson
(d) Chadwick.
3. An atom of atomic number 53 and mass number 127 contains how many
neutrons? (a) 53, (b) 74, (c) 127, (d) 180
127-53=74
40
4. How many electrons are in an atom 18Ar? (a) 20, (b) 22, (c) 40, (d) no correct
answers given.
Since no charge is given (if exists, the charge is given as
the superscript following the element symbol), it is a neutral atom so the number
of electrons must be equal to the number of protons: 18.
139
5. The number of neutrons in an atom 56 Ba is (a) 56, (b) 83, (c) 139, (d) no correct
number given.
# neutrons = mass # - atomic # = 139 – 56 = 83
6. The name of the isotope containing one proton and two neutrons is (a) protium
(b) deuterium, (c) tritium, (d) helium.
7. Each atom of specific element has the same (a) number of protons, (b) atomic
mass, (c) number of neutrons, (d) no correct answer given.
The identity of an element is defined by the number of protons.
23
23
7
6
8. Which pair of symbols represents isotopes? (a) 11Na and 12Na, (b) 3Li and 3Li, (c)
63
29Cu
29
12
12
and 64Cu, (d) 24Mg and 26Mg.
Isotopes must have the same atomic number, but different mass number.
9. Two naturally occurring isotopes of an element have masses and abundance as
follows: 54.00 amu (20.00%) and 56.00 amu(80.00%). What is the relative atomic
mass of the element? (a) 54.20, (b) 54.40, (c) 54.80, (d) 55.60.
Relative mass = 54.00 (20.00/100) + 65.00 (80.00/100) = 55.60.
10. Substance X has 13 protons, 14 neutrons and 10 electrons. Determine the
identity. (a) 27Mg, (b) 27Ne, (c) 27Al3+, (d) 27Al.
Since X has 13 protons, its identity is Al; however, it has only 10
electrons, i.e. three electrons less than protons, so its charge is 3+.
11. The mass of chlorine atom is 5.90 x 10-23 g. How many atoms are in a 42.0 g
sample of chlorine? (a) 2.48 x 10-21, (b) 7.12 x 1023, (c) 1.40 x 10-24, (d) no
correct number is given.
Make a proportion: 1 atom : 5.90 x 10-23 g = X atoms : 42.0 g
X = 42.0 g / (5.90 x 10-23 g) = 7.12 x 1023 atoms.
108
12. The number of neutrons in an atom 47 Ag is: (a) 47, (b) 108, (c) 155, (d) no
correct answer given.
(See Q.5) 108 - 47 = 61.
27
13. The number of electrons in an atom of 13Al is: (a) 13, (b) 14, (c) 27, (d) 40. See
Q.4 for explanation.
65
14. The number of protons in an atom of 30Zn is: (a) 65, (b) 35, (c) 30, (d) 95. The
number of protons is given by the atomic number, 30.
24
15. The number of electrons in the nucleus of an atom of 12Mg is: (a) 12, (b) 24, (c)
36, (d) no correct number given.
See Q.13 for explanation.
Putting it together, chapter 6 (p.125, Names and Formulas, q. 1-40)
In which of the following is the formula correct for the name given?
1.
copper(II) sulfate, CuSO4. OK
2.
ammonium hydroxide, NH4OH. OK
3.
mercury (I) carbonate, HgCO3. No, should be Hg2CO3.
4.
Phosphorus triiodide, PI3. OK
5.
Calcium acetate, Ca(C2H3O2)2. OK.
6.
hypochlorous acid, HClO. OK
7.
Dichlorine heptoxide, Cl2O7. OK
8.
Magnesium iodide, MgI. No, should be MgI2.
9.
Sulfurous acid, H2SO3. OK
10.
Potassium manganate, KMnO4. No, should be K2MnO4.
11.
Lead(II) chromate, PbCrO4. OK
12.
Ammonium hydrogen carbonate, NH4HCO3. OK
13.
Iron(II) phosphate, FePO4. No, should be Fe3(PO4)2.
14.
Calcium hydrogen sulfate, CaHSO4. OK
15.
Mercury(II) sulfate, HgSO4. OK
16.
Dinitrogen pentoxide, N2O5. OK
17.
Sodium hypochlorite, NaClO. OK
18.
Sodium dichromate, Na2Cr2O7. OK
19.
Cadmium cyanide, Cd(CN)2. OK
20.
Bismuth(III) oxide, Bi3O2. No, should be Bi2O3.
21.
Carbonic acid, H2CO3. OK
22.
Silver oxide, Ag2O. OK
23.
Ferric Iodide FeI2. No, should be FeI3.
24.
Tin(II) fluoride, TiF2. No, should be SnF2. Ti is symbol for titanium.
25.
Carbon monoxide, CO. OK
26.
Phosphoric acid, H3PO3. No, should be H3PO4. H3PO3 is phosphorous acid.
27.
Sodium bromate, Na2BrO3. No, should be NaBrO3.
28.
hydrosulfuric acid, H2S. OK
29.
Potassium hydroxide, KOH. OK
30.
Sodium carbonate, Na2CO3. OK
31.
Zinc sulfate, ZnSO3. No, should be ZnSO4. ZnSO3 is called zinc sulfite.
32.
Sulfur trioxide, SO3. OK.
33.
Tin(IV) nitrate, Sn(NO3)4. OK
34.
Ferrous sulfate, FeSO4. OK
35.
Chloric acid, HCl. No, should be HClO3. HCl is hydrochloric acid.
36.
Aluminum sulfide, Al2S3. OK
37.
Cobalt(II) chloride, CoCl2. OK
38.
Acetic acid, H2C2H3O2. OK
39.
Zinc oxide, ZnO2. No, should be ZnO.
40.
Stannous fluoride, SnF2. OK
Putting it together, chapter 8 (p.199, q. 23-35)
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
BaCl2 + (NH4)2CO3  BaCO3 + 2 NH4Cl is: an example of: (a) combination, (b)
decomposition, (c) single displacement, (d) double displacement
When the equation Al + O2  Al2O3 is properly balanced, which of the following
terms appears? (a) 2 Al,
(b) 2 Al2O3, (c) 3 Al,
(d) 2 O2
( Balanced eq.: 4Al + 3O2  2Al2O3 )
Which equation is improperly balanced?
(a) 2 KNO3  2 KNO2 + O2
(b) H2O2  H2O + O2
(c) 2 Na2O2 + 2 H2O  4 NaOH + O2
(d) 2H2O  2H2 + O2
The reaction 2 Al + 3 Br2  2AlBr3 is an example of: (a) combination, (b) single
displacement, (c) decomposition, (d) double displacement
Which of the following terms appears when the eq. PbO2  PbO + O2 is
balanced?
(a) PbO2,
(b) 3 O2,
(c) 3 PbO,
(d) O2
( Balanced eq.: 2 PbO2  2 PbO + O2)
Which of the terms appears when the eq. Cr2S3 + HCl  CrCl3 + H2S is
balanced?
(a) 3 HCl,
(b) CrCl3,
(c) 3 H2S,
(d) 2 Cr2S3
( Balanced eq.: Cr2S3 + 6 HCl  2 CrCl3 + 3 H2S)
When the eq. F2 + H2O  HF + O2 is balanced, one term is:
(a) 2 HF.
(b) 3 O2,
(c) 4 HF,
(d) 4 H2O
(Balanced eq.: 2 F2 + 2 H2O  4 HF + O2)
When the eq. NH4OH + H2SO4  is completed and balanced, one term is: (a)
NH4SO4,
(b) 2 H2O,
(c) H2OH,
(d) 2 (NH4)2SO4.
( Balanced eq.: 2 NH4OH + H2SO4  (NH4)2SO4 + 2 H2O)
When the eq. H2 + V2O5  V + is completed and balanced, one term is:
(a) 2 V2O5, (b) 3 H2O, (c) 2 V, (d) 8 H2.
( Balanced eq.: 5 H2 + V2O5  2 V + 5 H2O)
When the eq. Al(OH)3 + H2SO4  Al2(SO4)3 + H2O is balanced, the sum of the
coefficients will be: (a) 9, (b) 11, (c) 12, (d) 15
( Balanced eq.: 2 Al(OH)3 + 3 H2SO4  Al2(SO4)3 + 6 H2O)
When the eq. H3PO4 + Ca(OH)2  H2O + Ca3(PO4)2 is balanced, the proper
sequence of coefficients is (a) 3,2,1,6 (b) 2,3,6,1 (c) 2,3,1,6 (d) 2,3,3,1.
( Balanced eq.: 2 H3PO4 + 3 Ca(OH)2  6 H2O + Ca3(PO4)2 )
When the eq. Fe2(SO4)3 + Ba(OH)2  is completed and balanced, one term is:
(a) Ba2(SO4)3, (b) 2 Fe(OH)2, (c) 2 Fe2(SO4)3, (d) 2 Fe(OH)3.
( Balanced eq.: Fe2(SO4)3 + 3 Ba(OH)2  2 Fe(OH)3 + 3 BaSO4 )
Which of the following is not true for the eq: 2 H2 + O2  2 H2O + 572.4 kJ?
(a) Exotermic reaction, (b) 572.4 kJ liberated for every mole H2O formed, (c) 2
mol H2 reacts with 1 mol O2, (d) 572.4 kJ liberated for each 2 mol H2 reacted.
( 572.4 kJ is liberated per equation, two moles of water are formed )
Putting it together, chapter 10 (p.262, questions 1-18)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
The concept of electrons existing in specific orbits around the nucleus was the
contribution of (c) Bohr
Electron structure of fluorine is (a) 1s2 2s2 2p5.
The correct electron structure for 48Cd is (b) 1s22s22p63s23p64s23d104p65s24d10.
The correct e- structure for 23V is 1s2 2s2 2p6 3s2 3p6 4s2 3d3, or (a) [Ar] 4s2 3d3.
48
22 Ti stands for 22 e-, 22 p+, 26 n; answer (a)
The number of orbitals in a d sublevel is (b) 5. Check: Every orbital can hold up
to two electrons, so the total number of electrons in d sublevel is 10. That is why
there are 10 transition elements (groups 1B to 8B in periodic table).
The number of e- in the third principal energy level in an atom having the electron
structure 1s22s22p63s23p2 is (b) 4. Check: 2 e- in 3s, 2 e- in 3p orbital.
The total number of orbitals that contain at least one electron in an atom having
the structure 1s22s22p63s23p2 is (b) 8. Check: count: 1 orbital each for 1s2 and
2s2, 3 orbitals for 2p6, 1 orbital for 3s2 and 2 orbitals for 3p2. It is understood that
each electron in 3p is in its own orbital (rule of filling!), and the third 3p orbital is
empty.
Which of these elements has two s and six p electrons in its outer energy level?
(c) Ar Check: (a) H has no p electrons, (b) O has unfilled p orbital.
Which element is not a noble gas? (a) Ra. Check: Noble gases are group 8A
(He, Ne, Ar, Kr, Xe, Rn-radon). Element Ra (radium) is in group 2A..
Which element has the largest number of unpaired electrons? (d) N.
Count: F has 5 e- in p orbitals, two paired and one unpaired electron (2p5), S has
2 unpaired electrons (3p4), Cu has one unpaired electron (3d9), N has three
unpaired electrons (2p3).
How many unpaired electrons are in the electron structure of 24Cr, [Ar]4s13d5?
(d) 6. Check: one unpaired electron in s, and all five unpaired in d.
Groups 3A-7A plus the noble gases form the area of the periodic table where the
electron sublevels being filled are (b) s and p sublevels.
Check: d and f
sublevels are filled in transition elements, i.e. B-groups, d is filled in the main
group and and f sublevel is filled in inner transition element group, i.e. in actinide
and lanthanide series.
In moving down an A group on the periodic table, the number of electrons in the
outermost energy level (b) remains constant. That is how the periodic table is
made!
Which of the following is an incorrect formula? (c) AlO. Check: aluminum forms
compounds in which it is 3+ only. Thus, its oxide has the formula Al2O3.
Elements of the noble gas family (c) have an electron structure of ns2np6 (helium
is an exception), where n is the period number. Check: (a) is wrong because
there are few compounds known to exist with Xe, and (b) valence electrons are
filled in the noble gas family, but that does not mean a noble gas does not have
them!
The lanthanide and actinide series of elements are (b) transition elements.
Check Q13.
The element having the structure 1s2 2s2 2p6 3s2 3p2 is in Group (c) IVA.