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Average Atomic Mass (Test Review)

Total questions: 17

Worksheet time: 15mins

Name
Class
Date
1.
What is the atomic number?
a)
the number of protons
b)
the number of protons and neutrons
c)
the number of neutrons
d)
the number of protons and electrons
2.
What is the mass number defined as?
a)
the number of protons
b)
the number of protons and neutrons
c)
the number of neutrons
d)
the number of protons and electrons
3.
What is the atomic number of this atom?
a)
1
b)
3
c)
4
d)
7
4.

What is the mass number of this atom?

a)

1

b)

3

c)

4

d)

7

5.

What is the atomic number of Barium, Ba? (enlarge the periodic table)

a)

20

b)

38

c)

56

d)

88

6.

How many protons are in a sodium atom, Na? (tap to enlarge the periodic table)

a)

Sodium has 1 proton.

b)

Sodium has 3 protons.

c)

Sodium has 11 protons

7.

Atoms of the same element which have a different number of neutrons are called _________________.

a)

ions

b)

isotopes

c)

quarks

d)

molecules

8.

The average atomic mass on the periodic table is found from...

a)

calculating the weighted average mass of all the isotopes of that element

b)

Calculating different types of elements together

c)

calculations the average of all elements in that period together.

d)

making a guess about how much all the isotopes might wiegh together.

9.

The mass of an element is 15 and the number of protons is 7 how many neutrons does it have?

a)

15

b)

7

c)

8

d)

22

10.

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

a)

15.99, Oxygen

b)

10.81, Boron

c)

10.81, Oxygen

d)

15.99, Boron

11.

Which of the following represents isotopes of the same element?

a)

818O and 718O

b)

919F and 1019Ne

c)

919F and 919Ne

d)

816O and 818O

12.

What is the average atomic mass for thallium, Tl, if there are two isotopes with the following masses and abundances? Tl-203 has a mass of 203 amu with an abundance of 29.5 % Tl-205 has a mass of 205 amu with an abundance of 70.5 %

a)

203.12 amu

b)

204.31 amu

c)

204.41 amu

d)

204.0 amu

13.

A sample of cesium is 75% Cs-133, 20% Cs-132, and 5% Cs-134. What is the average atomic mass?

a)

132.97 amu

b)

133.00 amu

c)

133.16 amu

d)

132.85 amu

14.

To calculate average atomic mass, you need

a)

the atomic mass of each isotope

b)

the percent abundance of each isotope

c)

the atomic mass and percent abundance of each isotope

d)

to find the average of the atomic masses of each isotope

15.
A neutral atom of the isotope 2612Mg would consist of
a)
12 protons, 26 neutrons, 26 electrons
b)
26 protons, 12 neutrons, 26 electrons
c)
26 protons, 14 neutrons, 14 electrons
d)
12 protons, 14 neutrons, 12 electrons
16.
4.35% of all X atoms have a mass of 39.946 amu. 83.79% have a mass of 41.941 amu, 9.50% have a mass of 42.941 amu, and 2.36% have a mass of 43.939 amu. What is the average atomic mass of atom X?
a)
41.97 amu
b)
42.19 amu
c)
10.43 amu
d)
40.04 amu
17.

Calculate the average atomic mass of the element iron (Fe) using the following data:

[Isotope / % abundance]

[Iron 54 / 6% ] [Iron 56 / 92% ] [ Iron 57 / 2% ]

a)

53.7 amu

b)

54.9 amu

c)

5592.0 amu

d)

55.9 amu