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CHEM: Atomic Structure - Isotopes

Total questions: 24

Worksheet time: 18mins

Name
Class
Date
1.
What do these isotopes of carbon all have in common?
a)
neutrons & mass number
b)
atomic number and neutrons
c)
atomic number and electrons
d)
protons, atomic number, and mass number
2.
How many neutrons does the isotope of lithium have?
a)
8
b)
3
c)
4
d)
5
3.
How many neutrons in C-14?
a)
6
b)
7
c)
14
d)
8
4.
Isotopes are atoms of the same element with different #’s of __________ & therefore different __________.
a)
n0 ;  atomic #’s
b)
p+ ; atomic #’s
c)
e- ; atomic masses
d)
n0 ; atomic masses
5.
If X is the symbol for an element, which of the following two symbols represent    isotopes of the same element?     I. 7735X  II. 7733X  III. 8137X  IV. 8135 X
a)
I and II
b)
III and IV
c)
I and IV
d)
I and III
6.
How many neutrons does an atom of the isotope Neon-22 have?
a)
12
b)
10
c)
22
d)
20
7.
Four isotopes of lead include lead-204, lead-206, lead-207, and lead-208.  The average atomic mass of lead is 207.2.  Which isotope of lead is likely to be the most abundant.
a)
204
b)
206
c)
207
d)
208
8.
How many electrons are in an atom that has an atomic number of 34, an atomic mass of 74 and a charge of -2?
a)
34
b)
36
c)
2
d)
40
9.
How many neutrons does a Carbon 13 atom have?
a)
6
b)
5
c)
7
d)
8
10.

Rubidium has two common isotopes, 85Rb and 87Rb. If the abundance of 85Rb is 72.2% and the abundance of 87Rb is 27.8%, what is the average atomic mass of rubidium?

a)

85.468 amu

b)

37 amu

c)

85.6 amu

d)

86.4 amu

11.

There are two primary isotopes found in any sample of copper: copper-63 and copper-65. The isotope 65Cu composes 69.2% of the sample and 63Cu comprises the other 30.8%. Based on this data, what is the atomic mass of copper?

a)

29 amu

b)

63.546 amu

c)

64.4 amu

d)

63.6 amu

12.
If a sulfur atom has 16 protons, 16 electrons, and 16 neutrons, its atomic mass is:
a)
16
b)
32
c)
48
d)
64
13.
On the periodic table, how is atomic mass represented?
a)
As an average of the mass of different isotopes
b)
as the exact mass of every atom
c)
as the mass of the most common isotopes
d)
As the masses of all protons added together
14.
What do carbon-12 and carbon-14 have in common?
a)
they have same number of protons
b)
they have the same number of neutrons
c)
they have the same atomic mass
d)
they have the same atomic weight
15.
What is the name of the pictured isotope?
a)
Copper-29
b)
Copper-63
c)
Copper-34
d)
CopperWopperHopperBopper
16.
The relative mass of an electron is...
a)
1
b)
2
c)
0
d)
3
17.
The relative mass of a proton/neutron is.....
a)
0
b)
1
c)
2
d)
3
18.
In a stable atom the amount of electrons is electron is equal to
a)
neutrons
b)
protons
c)
atomic mass
d)
neutrons + protons
19.
What is the name of the pictured isotope?
a)
Carbon-12
b)
Carbon-13
c)
Carbon-14
d)
Carbon-15
20.
Carbon has an atomic number of 6 and an atomic mass of 12. Which elements are considered isotopes of carbon?
a)
Carbon-12
b)
Carbon-13
c)
Carbon-14
d)
Both Carbon-13 and Carbon-14
21.

An element has three isotopes. Given the abundances and relative masses, calculate the average atomic mass and determine (from the periodic table) which element it is.


Abundances | Relative masses

0.005% | 234.04 amu

0.720% | 235.04 amu

99.275% | 238.05 amu

a)

Uranium (#92, Atomic Mass: 238.03 amu)

b)

Fluorine (#9, Atomic Mass: 19.00 amu)

c)

Mercury (#89, Atomic Mass: 200.59 amu)

d)

Polonium (#84 209 amu)

22.

76 protons and 114 neutrons

a)

Osmium-114

b)

Osmium-76

c)

Osmium-190

d)

Osmium-190.23

23.

The number of protons + neutrons in the nucleus is referred to as what?

a)

Atomic number

b)

Atomic mass

c)

Mass number

d)

Isotope number

24.

Atoms of the same element with a different number of electrons are called ___________.

a)

elements

b)

isotopes

c)

ions

d)

neutral