A. Definitions (2 points each)
1. Chemistry - is the study of the structure and properties
of matter, and the changes that matter undergoes
2. _Hypothesis_ is an educated guess as
to how or why something happens.
3. Accuracy - How close a measurement is to the "true"
value
4. _Mass_ is the amount of matter in an object.
5. Element - is a pure substance composed of only one
type of atom
6. _homogenous misture_ is a uniform mixture
of 2 or more compounds
7. Compound - is a pure substance composed of more
than one type of atom
8. _Density_ is the mass of an object divided by its
volume.
9. Precision - how close multiple measurements are
to each other
10. _Temperature_ is a measure of a molecules kinetic
energy.
B. Concepts
11. Complete the following table of measurements.
(4 points)
Measurement
SI unit, abbreviation
length
m
_mass_
kg
_density_
g/cm3
temperature
__K___
volume
__m3___
12. Complete the following table of prefixes. (7 points)
Prefix
Abbreviation
Exponential factor
mega-
M
106
micro-
__µ___
10-6
kilo-
__k___
_103_
_centi-_
__c___
10-2
_milli-_
m
_10-3_
13. How many significant figures are in the following
measurements? (5 points)
2.70 g/cm3
3
113 K
3
0.0026 g
2
27,000
2
5.01 X 10-2 m
3
14. How many protons, neutrons and electrons does an
atom of 40Ca have? (3 points)
atomic number is 20, therefore 20 protons
protons = electrons, so 20 electrons
neutrons = atomic mass - atomic number = 40-20 = 20 neutrons
15. Construct a table outlining the charge, mass and
location of the subatomic particles. (6 points)
particle charge mass
location
proton +1
1 amu nucleus
neutron 0
1 amu nucleus
electron -1
0 amu cloud surrounding nucleus
16. Write the electron configurations for the following
elements. (6 points)
Ca 1s22s22p63s23p24s2
N 1s22s22p3
Ne 1s22s22p6
17. What are the major properties of the typical metals
and nonmetals? (4 points)
property
metals
nonmetals
state
solid
liquid or gas
conductivity conductors
insulators
luster
shiny
dull
malealbilty
mallable/ductile brittle
18. Compute the mean density of the following unknown
liquid. Express your answer in the correct number of significant figures.
(5 points)
Volume, measured
Mass, measured
Trial 1
9.81 mL
12.327 g
Trial 2
9.83 mL
12.179 g
Trial 3
9.92 mL
12.204 g
Average
= 9.853333
12.23667
Density = mass/volume
= 12.23667 g/9.853333 mL
Density = 1.24 g/mL
19. Give the name for each of the following elemental
symbols. (4 points)
Ne _Neon______
F _Fluorine______
Ca _Calcium______
S _Sulfur_______
20. Describe the periodic trends for size and electronegativity.
(4 points)
size increases as you go right to left and top to bottom (Cs largest common)
electronegativity increases as you go left to right and bottom to top (F
highest)
21. What oxidation state will the following atoms develop?
(3 points)
F -1
Mg +2
S -2
22. Describe the difference between mass and weight.
(4 points)
mass is the amount of matter present (always the same)
weight is influenced by gravity (less on moon than earth)
23. Give the symbol for each of the following elements.
(5 points)
potassium __K_____
silicon ___Si______
actinium __Ac_______
krypton ___Kr_____
boron ___B_____
24. List the names of 4 groups of elements.
(8 points)
alkali metals, alkaline earth metals, transition elements, halogens, noble
gasses
25. How many periods exist in the modern periodic
table of the elements? (1 point)
7
26. State the periodic law. ( 5 points)
When atoms are arranged according to atomic number, their chemical
and physical properties show periodic trends.
27. How many valence electrons do the following elements
have? (3 points)
Na 1
B 3
Ne 8
28. What is a valence electron anyway? (2 points)
An electron in the outer shell, no matter what principle energy level it
is in.