Atomic Mass Number Worksheet
A Grade 8 science worksheet focusing on understanding atomic mass number, atomic number, protons, neutrons, and electrons.
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Atomic Mass Number Worksheet
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Read each question carefully and answer to the best of your ability. Use the provided illustration to help you understand the parts of an atom.
Diagram of an Atom

1. What does the atomic number represent?
Number of neutrons
Number of protons
Number of electrons
Total number of particles in the nucleus
2. An atom has 6 protons and 6 neutrons. What is its atomic mass number?
6
12
0
Cannot be determined
3. The atomic mass number is the sum of and in an atom's nucleus.
4. All atoms of the same element have the same number of .
5. The number of electrons in a neutral atom is equal to its atomic number.
True
False
6. Isotopes of an element have different numbers of protons.
True
False
7. An atom of oxygen has an atomic number of 8 and an atomic mass number of 16. How many neutrons does it have? Show your work.
8. Explain the difference between atomic number and atomic mass number.