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PAP FALL SEMESTER EXAM REVIEW 2012 KEY
Explain the difference between each pair of terms.
1.
Pure substances vs. mixtures
a. Pure substance – substance that has a fixed (non-changing) composition with the same properties
and characteristics in every sample (elements and compounds)
b. Mixtures – substance that has a variable (changing) composition made up of two or more types of
matter
2.
elements vs. compounds
a. element – pure substance made up of only one type of atom (anything on the periodic table)
b. compounds – substance that is made from the chemical combination of two or more different types
of atoms
3.
physical properties vs. chemical properties
a. physical – a characteristic that can be observed or measured without changing the identity of the
substance
b. chemical – the ability of a substance to undergo a change that transforms it into a different
substance
4.
extensive vs. intensive properties
a. extensive – property that depends on the amount of matter present
b. intensive – property that depends on the identity of the substance
5.
6.
Classify changes of matter as physical or chemical.
____P____
A piece of metal is heated until it turns red.
____C____
Aluminum and oxygen react to produce aluminum oxide.
____C____
An iron nail rusts.
____P____
A piece of copper metal is hammered into a thin sheet.
____P____
An ice cube melts.
____C____
Hydrochloric acid neutralizes sodium hydroxide to form sodium chloride and water.
____P____
Magnesium chloride is dissolved in water
Define the following terms.
atomic number – number of protons in an atom (also number of electrons in neutral atom)
mass number – sum of protons and neutrons in the nucleus of an atom
average atomic mass – average mass of all naturally occurring isotopes of an atom (on the periodic
table)
isotope – atoms of the same element with different mass numbers (same protons, different neutrons)
ion – an atom with a charge (uneven amount of protons and electrons)
valence electrons – electrons in the outer shell of the atom (used in chemical bonding)
Octet Rule – atoms gain, lose and share electrons to get 8 valence electrons (full outer shell)
electronegativity – the ability of an atoms to pull electrons towards itself in a bond
ionization energy – energy required to remove a valence electron
atomic radius – the size of an atom
7. Arrange each group of elements in order of increasing ionization energy.
a. F, Br, I, Cl
I BrClF
b. Ga, Al, Tl, B
TlGaAlB
c. Al, Si, Cl, S
AlSiSCl
8. For each group of elements, choose the element with the smallest atomic radius.
a. Na, Li, K, Fr
Li
b. Tc, Rh, Zr, Y
Rh
c. Hf, Cs, Pb, Pt
Pb
9. For each group of elements, choose the element with the greatest electronegativity.
a. He, Rn, Xe, Ar
b. As, N, P, Bi
He
c. Ba, Hf, Os, Hg
N
Hg
10. In general, ionization energies of the elements increase across each period and generally decrease
down each group.
11. In general, electronegativities of the elements increase across each period and generally decrease
down each group.
12. In general, the atomic radii of the element increases down a group and decreases across each period.
13. The atomic radii of group 3 elements are generally larger than the atomic radii of group 6 elements.
14. The atomic radii of period 2 elements are generally smaller than the atomic radii of period 6 elements.
15. The modern periodic table is arranged according to increasing atomic number.
16. Label the number of valence electrons for each group:
1 __1__ 2___2___ 13___3___ 14 __4___ 15 __5___ 16 ___6___ 17 ___7____ 18 ___8___
17. Elements in the same family have similar characteristics/properties.
18. List group numbers or describe the location of each of the following groups of elements.
19. Contrast the properties of metals and nonmetals. Explain the location of each on the periodic table.
• Metals - Properties:
• Properties:
– lustrous (shiny)
– Dull appearance
– good conductors of heat & electricity
– Brittle when solids
– malleable & ductile
– Do not conduct heat or electricity well
– solids at RT (except Hg)
– May be solid, liquid or gas at RT
20. Identify the location in the atom, mass, charge, and volume for each of the subatomic particles
a. proton – nucleus, 1 amu, +1, no volume
b. neutron - nucleus, 1 amu, no charge, no volume
c. electron – electron cloud, 0 amu, -1, all volume of the atom
21. Describe the experiments and their conclusions for:
a. JJ Thompson - used the cathode ray tube to discover the 1st subatomic particle - the electron
b. Ernest Rutherford - gold foil experiment - expected all of the radiation to pass through and was very
surprised when some of the particles were deflected - led to the discovery of the NUCLEUS and the
theory of the nuclear atom. Also discovered the proton.
22. Sketch the evolution of the atomic model. Include the name of the model and the scientist associated
with it.
Thomson's Plum Pudding
Rutherford
Bohr
Modern Electron Cloud
23. An element consists of three naturally occurring isotopes with the following mass numbers: 24, 25 and
26. The relative abundances of these three isotopes are 78.70, 10.13 and 11.17 percent respectively.
Calculate the average atomic mass and identify the element. Show your work! (24.32 amu)
(24 x .7870) + (25 x .1013) + (26 x .1117)
24. A naturally occurring element, X, exists as 92.21% 28X, which has an atomic mass of 27.97693 amu,
4.70% 29X, which has an atomic mass of 28.97659 amu, and 3.09% 30X, which has an atomic mass of
29.97376amu. Calculate the average atomic mass and identify the element. Show your work! (28.11
amu)
(28 x .9221) + (29 x .0470) + (30 x .0309)
25. Complete the following chart.
Isotope
Name
Carbon-13
Nitrogen - 17
Boron - 5
Francium -223
Nuclear
Symbol
Atomic
Number
Mass Number
# of Protons
# of Neutrons
# of Electrons
6C
6
13
6
7
6
N
7
17
7
10
7
5B
5
11
5
6
5
87Fr
87
223
87
136
87
13
17
7
11
223
26. The electron configuration s2p6 represents
a. A halogen
b. A metalloid
c. A noble gas
Write the complete electron configuration, Noble gas configuration, orbital notation, dot diagram, and quantum
numbers for the following elements.
27. Selenium (Se) – number of electrons _______34____________
complete e – configuration: 1s22s22p63s23p64s23d104p4
Noble gas notation: [Ar]4s23d104p4
Dot diagram:
All orbitals full with arrows in opposite directions through 3d
Orbital notation: 1s ___ 2s___2p___ ____ ____3s___3p___ ____ ___4s___3d___ ___ ___ ___ ___4p___ ___ ___
Quantum numbers 4,1,-1,- ½
28. Chromium (Cr) – number of electrons ________24___________
complete e – configuration: 1s22s22p63s23p64s23d4
Noble gas notation: [Ar]4s23d4
All orbitals full with arrows in opposite directions through 4s
Orbital notation: 1s ___ 2s___2p___ ____ ____3s___3p___ ____ ___4s___3d___ ___ ___ ___ ___
Quantum numbers: 3, 2, 1, + ½
29. Magnesium (Mg) – number of electrons _______12____________
complete e – configuration: 1s22s22p63s2
Noble gas notation: [Ne]3s2
Dot diagram:
All orbitals full with arrows in opposite directions through 2p
Orbital notation: 1s ___ 2s___2p___ ____ ____3s___
Quantum numbers: 3, 0,0, - ½
30. Complete the following table about nuclear particles:
Particle
Charge
Composition
Penetrating Power (can
be stopped by…)
α
+2
2 protons, 2 neutrons
(helium nuclei)
Paper, cloth
β
-1
Electron
Wood, concrete
0
Electromagnetic
waves
Lead, 6ft concrete
Symbol
Alpha
4
2He,
Beta
0
-1e,
Gamma
γ
Balancing Nuclear Equations
31. 23994Pu + 10n  24094Pu
32. 10745Rh  10746Pd + 0-1e
33. 126 C+ 24496Cm  254102No + 210n
34. 42He + 2713Al  3014Si + 11H
35. 23892U + 10n  23992U
36. 115B + 25198Cf 
259
103Lr
+ 310n
37. Define the following terms
chemical bond – any force that holds two or more atoms together
cation – positively charged ion (metals, lost electrons)
anion – negatively charged ion (nonmetals, gained electrons)
ionic bond – electrostatic attraction between cations and anions after a transfer of electrons
covalent bond – two nonmetals sharing electrons
metallic bond – pure metals bonding through the sea of electrons
electron sea model – stationary metal nuclei release their valence electrons which are free to float
between them all
38. Write names for the following compounds
Sodium sulfate Na2(SO4)
Ammonium sulfide (NH4)2S
Barium phosphide Ba3P2
39. Write formulas for the following compounds.
Sr(NO3)2
strontium nitrate
P4Cl10
tetraphosphorus decachloride
N3O7
trinitrogen heptoxide
Cu(C2H3O2)2
copper (II) acetate
Lead (IV) hydroxide Pb(OH)4
Tin (II) hydroxide Sn(OH)2
Iron (II) carbonate Fe(CO3)
Carbon dioxide CO2
Cd(NO3)2
Li2CO3
Zn3(PO2)2
cadmium nitrate
lithium carbonate
zinc hypophosphite
40. Differentiate between fission and fusion reactions.
Fission splits a large nucleus into smaller nuclei. Fusion combines two small nuclei into one larger one.
41. Briefly describe what happens that allows you to see colors in the flame tests and the gas tubes.
When energy is added to an atom, an electron jumps to a higher energy level (excited state). It does not
stay in the excited state for long, so as it falls back to its original location (ground state), it releases
energy in the form of electromagnetic radiation which based on energy, frequency and wavelength will
show as a different color.
42. What is the energy of a quantum of light with a frequency of 4.31 X 1014 1/s or Hz? (2.86 x 10-19 J)
E = hv = (6.63 x 10-34 Js)( 4.31 X 1014 Hz)
43. A certain violet light has a wavelength of 413 nm. What is the frequency of the light? (7.26 x 1014 Hz)
c = vλ  v = c/λ = (3.0 x 108 m/s) / (413 x 10-9 m)
44. What is the energy of light with a wavelength of 662 nm? (3.00 x 10-19 J)
c = vλ  v = c/λ = (3.0 x 108 m/s) / (662 x 10-9 m) = 4.53 x 1014 Hz
E = hv = (6.63 x 10-34 Js)( 4.53 X 1014 Hz)
45. For each substance listed below draw the Lewis structure, determine the geometric shape, and
polarity.
H2S
bent (104.5°)
polar
SiF4
tetrahedral (109.5°)
nonpolar
PH3
trigonal pyramidal (107°)
N2
linear (180°)
NO2-
bent (104.5°)
SO3
trigonal planar (120°)
polar
nonpolar
polar
nonpolar
46. For sodium sulfate, calculate the percent composition of each element. (32.4% Na, 45.1% O, 22.6% S)
47. How many moles are in 30g of NaCl? (0.5 moles)
48. How many molecules are in 3.00 moles of KCl? (1.81X1024 molecules)
49. What is the empirical formula for a compound which contains 67.1% zinc and the rest is oxygen? (ZnO2)
50. If the empirical formula of a compound is CH and the molecular mass is 78.12g/mol, what is the
molecular formula?
51. How many grams are in 5 moles of H2O? (90 grams)