Chemistry Fall Final Review 2012-2013
Alchemy Unit
1. Using the periodic table, where are the metals and nonmetals? What is hydrogen?
Metals are in the left side of the periodic table. Nonmetals are on the right side of the periodic table.
Hydrogen is an nonmetal.
2. Where are the alkali, alkaline earth, transition metals, halogens, and noble gases?
Alkali metals = group 1, alkaline earth metals = group 2, transition metals = middle of periodic table,
halogens = group 7, and noble gas = group 8
3. On the periodic table, what are the trends for atomic mass, atomic number, atomic radii(size), and
reactivity as you move across a period and down a group?
On the periodic table:
Atomic mass increases from left to right and top to bottom
Atomic numbers increase from left to right and top to bottom
Atomic radii increases from top to bottom and right to left
Reactivity: Metals increase from top to bottom
Nonmetal increases from bottom to top
4. Draw a Bohr atomic model of lithium. Label the parts of the atom and their charges.
Nucleus is in the center and contains the protons (positive charges) and neutrons
(neutral). Electrons are negatively charged and they on the two shells.
a).Which part of the atom is the heaviest and lightest?
The nucleus is the heaviest part of the atom. The electrons are the lightest in weight.
5. What is the atomic number and atomic mass of phosphorus and strontium?
P: atomic number =15, atomic mass = 30.97 amu
Sr: atomic # = 38, atomic mass = 87.62 amu
a). What is the difference between atomic number and atomic mass?
Atomic number is the number of protons. Atomic mass is the weight of an atom (protons plus neutrons).
6. What is an isotope? Name two possible isotopes for carbon and potassium.
An isotope is atom that can have different number of neutrons.
Carbon -12 and Carbon-13; Potassium-39 and Potassium-40
7. a). Write the equation for the alpha decay of astatine -213.
b). Write the equation for the beta decay of neptunium -239.
c) What is more harmful alpha particles, beta particles, or gamma rays?
213
4
209
85As→ 2 He +
83 Bi
239
239
0
93 Np →
94 Pu + -1 e
Gamma rays are the most harmful then beta particles and finally alpha particles.
8. What are valence electrons? Which subshells are included in valence?
Valence electrons are the electrons on an atom’s outer shell. Valence electrons are on the s and p
subshells.
a) How many valence electrons do Mg, S, and Al have?
Mg = 2, S=6, Al=3
9. What elements have the following electron configurations of
a). 1s22s22p63s23p64s23d104p1 Gallium
b). 1s22s22p63s23p4 Sulfur
10. Fill in table.
Type of Bond
Conducts
Electricity?
Dissolves in
water?
Metals
Metallic
Yes
No
Metal and Nonmetal
Ionic
No
Yes
Nonmetals (hard solids)
Covalent Network
No
No
Nonmetals (l, g, soft solids)
Molecular Covalent
Yes
Yes
Conducts electricity
when dissolved?
Yes
No
11. What are ions? What are cations and anions?
Ions are atoms that have lost or gain electrons and become positive or negative charged. Cation is a
positive ion and an anion is a negative ion.
12. In ionic bonds, metals tend to lose electrons and nonmetals gain electrons. What happens to these
elements to achieve noble electron configuration? What charge does the element form?
a). oxygen Gain 2 electrons and become O-2
b). chlorine Gain 1 electron and become Cl-1
+1
c). sodium
Lose 1 electron and become Na
d). barium
Lose 2 electrons and become Ba+2
13. a). What is the chemical formula and name of the compound formed when beryllium reacts with
fluorine?
b). What is the chemical formula and name of the compound formed when when potassium reacts with
sulfur?
Be will lose 2 electrons and F will gain 1 electron. Be+2 and F-1 will crisscross charges and form BeF2,
beryllium fluoride.
K will lose 1 electron and S will gain 2 electrons. K+1 and S-2 will crisscross charges to form K2S,
potassium sulfide.
14. What are the chemical formula and charge for the following polyatomic ions?
a). sulfate
b) hydroxide
c) nitrate
-1
OH
hydroxide
SO4 -2
sulfate
-1
NO3
nitrate
Smells Unit
15. What are isomers? Draw the three isomers for C3H9N.
An isomer is when a molecule has the same molecular formula but different structural formulas.
Any three of the structures below are correct.
16. What is the HONC1234 and Octet rule? Which molecules
obey the Octet rule? Draw the Lewis Dot structures for the
following molecules.
a). CF3
b). PCl2
c). OCl2
d). SiI4
HONC1234 rules states that hydrogen bonds once,
oxygen bonds twice, nitrogen bonds three times, and carbon bonds four times. The octet rules states that
elements need to obtain eight valence electrons through bonding to be stable. Only c and d obey the octet
rules.
..
:I:
.. .. ..
.. .. ..
:I:Si:I:
:Cl:O:Cl:
˙˙˙˙ ˙˙
˙˙ ˙˙ ˙˙
:I:
˙˙
17. What are the different functional groups, the smells associated for each, and their common names
endings?
Functional Group
Structure
Smell
Name endings
Ester
O=C-O-C
Sweet
“-ate”
Carboxylic Acid
O=C-O-H
Putrid
“-acid”
Ketone
O=C
Minty
“-one”
Alcohol
C-O-H
Camphor, Minty, Sweet
“-ol”
Amine
C-N
Fishy
“-amine”
18. What is an electron domain? What is the difference between lone pairs and bonded electron pairs?
Electron domains are set of electrons (bonded or lone) that surround an atom. Lone pairs are electrons that
are from the same atom. Bonded pair are electrons that from two different atoms in a bond.
19. Fill in table.
Molecule Lewis Dot Structure
Structural Formula and
Lone pairs on
Bonded
Name of Shape
central atom
pairs
CO2
..
..
O=C=O
Linear
0
4
:O::C::O:
SeCl2
Se
.. .. ..
:Cl:Se:Cl:
˙˙ ˙˙ ˙˙
/
Cl
Bent
2
2
\
Cl
NH3
..
H:N:H
˙˙
H
N
/ | \
H H H
Pyramidal
1
3
CH4
H
..
H:C:H
˙˙
H
H
Tetrahedral
|
C
/ | \
H H H
O
Trigonal
||
Planar
C
/ \
H H
0
4
0
4
CH2O
H
.. ..
H:C::O:
20. What is a catalyst? What does it do?
A catalyst is a substance that is not a reactant or product but added to a reaction to accelerate the reaction
time.
21. Write the molecular formula, structural formula, Lewis Dot structure, and ball-and-stick formula for
water.
Molecular formula
H2O
Structural Formula
Lewis Dot Structure
Ball and Stick Model
22. What are the different characteristics between a polar vs. nonpolar molecules? (ex: dissolve in water,
attraction to a negatively charged wand, on wax paper).
Polar Molecules
Nonpolar Molecules
Partial charges
No charge
Dissolve in water
Does not dissolve in water
Attract to charged wand
No attract to charged wand
Bead up (droplet)
Spreads out
Smells
Does not smell
23. How do you use the electronegativity values chart to determine nonpolar covalent, polar covalent, and
ionic bonds? What is happening to the electrons in these different bonds?
Nonpolar covalent bonds have electronegativity difference between 0-0.3 and there is equal sharing of
electrons.
Polar covalent bonds have ED between 0.4-1.8 and there is unequally sharing of electrons.
Ionic bonds have ED 1.9 or higher and there is losing and gaining of electrons.
24. Determine type of bond between these atoms: Cl-Cl, As-H, Ca-O, P-I, K-Cl, and Si-F
Cl-Cl 3.16-3.16=0
Nonpolar covalent bond
As-H 2.18-2.10=0.08
Nonpolar covalent bond
O-Ca 3.44-1.00=2.44
Ionic bond
I-P
2.66-2.19=0.47
Polar covalent
Cl-K 3.16-0.82=2.34
Ionic bond
F-Si 3.98-1.90= 2.08
Polar covalent (not ionic because the two elements are nonmetals)
25. Are the following molecules polar or nonpolar molecules? Explain
a). SiF4
b). PI3
a). SiF4 is nonpolar. The bonding between Si and F is polar covalent. The tetrahedral shape of the
molecule is symmetrical which cancels out the partial charges. The resulting molecule is nonpolar.
b). PI3 is polar. The bond between P and I is polar covalent. The pyramidal shape of the molecule is not
symmetrical so the partial charges remain to result in a polar molecule.
26. What are van der Waals forces: hydrogen bonding, dipole-dipole forces, and London Dispersion forces?
Hydrogen bonding is the way polar molecules that contain hydrogen stick together. Specifically,
hydrogen in a molecule is partially positive is attracted to the partially negative atom (F, O, N) in
another molecule.
Hydrogen bonding is illustrated with the dash lines.
Dipole-dipole forces are the way polar molecules stick together. Like hydrogen bonding, the partial positive
end attracts to the partial negative end of another molecule.
London dispersion forces are the way nonpolar molecules stick together. Nonpolar molecules have
temporary dipoles which create temporary partial negative and positive ends. These temporary charges
attract to each other.