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Parts of an Atom and Average Mass

Total questions: 8

Worksheet time: 16mins

Name
Class
Date
1.

The element copper has naturally occurring isotopes the first is 62.93amu at 69.2% abundance and the second is 64.93amu at 30.8% abundance. What is the average atomic mass of copper?

a)

63.55 amu

b)

63.54 amu

c)

63 amu

d)

64 amu

2.

Calculate the average atomic mass of sulfur if 95.00% of all sulfur atoms have a mass of 31.972 amu, 0.76% have a mass of 32.971 amu and 4.22% have a mass of 33.967 amu.

a)

32.05 amu

b)

32.06 amu

c)

33 amu

d)

34 amu

3.

Naturally occurring isotopes of strontium are: 0.56% are Sr-84, 9.86% are Sr-86, 7.00% are Sr-87 and 82.58% are Sr-88. What is the average atomic mass?

a)

87.71 amu

b)

87 amu

c)

84

d)

86

4.

Potassium is an alkali metal that is one of the electrolytes needed by the human body to conduct nerve impulses. The majority of potassium (93.26%) occurs as potassium-39. The rest is either potassium-40 (0.01%) or potassium-41 (6.73%).

a)

39.13 amu

b)

40 amu

c)

38 amu

d)

93.31 amu

5.

Zirconium is an element that makes up the cubic zirconia crystal that is commonly used as a cheap replacement for diamond. Zirconium has the following naturally occurring isotopes:

a)

91.21 amu

b)

92 amu

c)

19.21amu

d)

93 amu

6.

Calcium is a metal that is part of bone. It has several naturally-occurring isotopes. Calculate the average atomic mass.

a)

40.07 amu

b)

40.08 amu

c)

40 amu

d)

41 amu

7.

Tungsten is a metal found in the inner filaments of incandescent light bulbs. It has five naturally- occurring isotopes. Calculate the average atomic mass.

a)

183.84 amu

b)

183 amu

c)

183.9 amu

d)

183.85 amu

8.

There is more hydrogen present in the universe than any other element. 99.99% of all hydrogen is the hydrogen-1 isotope. The other 0.01% is hydrogen-2, also called deuterium.

a)

1.0078 amu

b)

1.0001 amu

c)

1.0199 amu

d)

2 amu