H Ch 4 Homework:
Problems:
1. Calculate the atomic mass of the following:
.10858
3.0504
6.9048
117.7216
.089% Te-122
2.46% Te-124
5.48% Te-126
91.97% Te-128
127.78538
2. Calculate the atomic mass of the following:
14.364
19.7496
5.8976
27.0396
5.6648
20.52% Ge-70 27.43% Ge-72 7.76% Ge-73 36.54% Ge-74 7.76% Ge-76
72.7156
Review:
1. Compare and contrast the three types of sub atomic particles in terms of location in the
atom, mass, and charge.
p – large mass, found in nucleus, positive charge
e – small mass, electron cloud, negative charge
n – large mass, nucleus, no charge
2. Define each of the following:
atomic mass
atomic number
p+n
# of p
3. Determine the number of protons, electrons, and neutrons in each of the following:
sodium-25
66
29 p/e, 37 n 110 47 p/e, 63 n
Cu
Ag
calcium-42
20 p, 20 e, 22 n
29
47
4. Write the nuclear symbol and hyphen notation for each of the following:
a) atomic mass = 28
b) 26 protons
c) 56 electrons
11 p, 11 e, 14 n
atomic number = 14
30 neutrons
82 neutrons
28
14Si
56
26Fe
138
56Ba
Si - 28
Fe - 56
Ba -138
5. State the law of conservation of mass-energy. Energy/mass are not created or
destroyed
State the law of definite composition. Regardless of the size of the sample or the
source, the same compounds have the same chemical composition.
State the law of multiple proportions. The same elements can combine in multiple
small whole number mass (mole) ratios
6. According to the law of conservation of mass, if element A has a mass of 2 and
element B has a mass of 3, then compound AB would have a mass of?
5
7. If 6 g of element K combine with 17 g of element L, how many grams of K will
combine with 85 g of L?
30g
What law is this an example of? Definite composition
8. If 60 g of X combine with 10 g of Y to form the compound XY, how many grams of
Y will be needed to combine with the same amount of X to form the compound XY2?
20g
What law is this an example of? Multiple proportions
9. What one factor determines the identity of an atom.
10. What are isotopes?
# of protons
Same element with a different mass
11. How are the isotopes of a particular element alike? How are they different?
Same number of protons. Different number of neutrons.
12. Explain how the electron was discovered.
Cathode ray tube…
13. Explain Rutherford’s experiment that led to the discovery of the nucleus. Gold foil
experiment…
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