FuseSchool: Atomic Number & Mass Number

What does the atomic number (Z) of an element represent?

• The total number of protons and neutrons

• The number of electrons

• The number of protons

• The number of neutrons

What does the mass number (A) of an element represent?

• The number of protons

• The total number of protons and neutrons

• The number of electrons

• The number of neutrons

What is the relative mass of an electron compared to protons and neutrons?

• Significantly larger

• Approximately the same

• So small it's usually not considered

• Exactly half

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An atom of Oxygen (O) has a mass number of 16 and an atomic number of 8. How many neutrons does it have?

• 16

• 8

• 24

• 0