1. Which distinguishes an atom of 2. An element with an atomic
one element from an atom of a
number of 51 and an atomic
different element?
mass of 121 has how many
neutrons in each atom?
A. the number of protons
B. the number of neutrons
A. 51
C. the number of electrons
B. 70
D. the number of neutrons and
C. 121
protons
D. 172
3. How many protons are in an
atom of bromine?
A. 115
B. 80
C. 45
D. 35
5. What is the atomic number of
carbon-14?
A. 6
B. 7
C. 12
D. 14
4. What is the mass number in
atomic mass units of an atom
with 14 protons, 14 electrons,
and 16 neutrons?
A. 14 amu
B. 16 amu
C. 30 amu
D. 44 amu
6. How do the atoms of carbon-12
and carbon-14 differ?
A. atomic number
B. number of electrons
C. number of protons
D. number of neutrons
7. Li-12 has how many protons?
A. 12
8. Atoms of a certain isotope have
25 neutrons and a mass number
of 45. What is the name of this
isotope?
B. 7
A. Calcium
C. 3
B. Yitterbium
D. 9
C. Manganese
D. Rhodium
9. Which of the following are isotopes of 10. Atoms of a certain isotope have
each other?
12 neutrons and a mass number of
A. An atom with 17 protons and 18
neutrons?
B. An atom with atomic number
16 and atomic mass 32?
24. How many electrons do they
have?
A. 24
B. 36
C. An atom with atomic number
16 and 18 neutrons?
D. An atom with 8 protons and 8
neutrons?
C. 12
D. It lost its electrons
11. A neutral atom contains 18
12. How many valence electrons
protons. How many electrons
would we find in an atom of
would it have if the atomic mass is aluminum?
25?
A. 13
A. 25
B. 27
B. 7
C. 3
C. 43
D. 14
D. 18
13. An atom has an atomic
number of 16. From this
number we know the
A. the number of protons
B. the number of neutrons
C. the number of neutrons &
electrons
D. the number of neutrons and
protons
15. How many protons are in an
atom of silicon?
A. 16
B. 14
C. 42
D. 28
17. What is the atomic number
of magnesium-26?
A. 26
B. 14
C. 12
D. 38
14. An element with an atomic
number of 9 and an atomic
mass of 23 has how many
neutrons in each atom?
A. 23
B. 32
C. 9
D. 14
16. What is the mass number in
atomic mass units of an
atom with 19 protons, 19
electrons, and 25 neutrons?
A. 19 amu
B. 44 amu
C. 25 amu
D. 38 amu
18. How do the atoms of
magnesuim-24 and
magnesuim-26 differ?
E. atomic number
F. number of electrons
G. number of protons
H. number of neutrons
20. Atoms of a certain
isotope have 15 neutrons and
a mass number of 26. What
is the name of this isotope?
19. O-20 has how many
protons?
A. 8
A. Lithium
B. 20
B. Sodium
C. 16
C. Phosphorus
D. 12
21. Which of the following is an isotope?
A. An atom with 7 protons and 7
neutrons?
B. An atom with atomic number 9
and atomic mass 25?
C. An atom with atomic number 3
and 7 neutrons?
D. An atom with 4 protons and 9
neutrons?
D. Iron
22. Atoms of a certain isotope
have 6 neutrons and a mass
number of 11. How many
electrons do they have?
A. 6
B. 11
C. 5
D. 10
23. A neutral atom contains 15
24. How many valence electrons
protons. How many electrons
would we find in an atom of
would it have if the atomic mass is fluorine?
31?
A. 9
A. 15
B. 7
B. 31
C. 19
C. 16
D. 10
D. 46
25. What can you conclude from this data?
Sample #
# protons
# neutrons
1
15
15
2
15
16
3
16
16
4
17
17
26.
5
B
10.811
A. Each sample has a different mass number.
The number 10.811 refers to the atom’s
A. Atomic number
B. Each sample is an atom of a different element
B. Number of particles in nucleus
C. Each sample is an isotope of the same atom.
D. Each sample has the same # of electrons as
protons.
27.
10
Ne
20.180
The number 10 refers to an atom’s
A. Number of protons
B. Number of protons and
neutrons
C. Number of neutrons
D. Atomic mass number
29.
6
C
12.011
The number 6 refers to the element’s
A. Atomic mass
B. Atomic number
C. Number of neutrons
D. Number of energy levels
C. Number of electrons
D. Number of neutrons
28. Magnesium has how many
electrons in the 3rd energy level?
A. 24
B. 8
C. 12
D. 2
30. The atomic number of an
atom identifies the number of
(A). protons.
(B). neutrons.
(C). protons and neutrons
(D). electrons and neutrons.