Atomic Structure and Isotopes

What determines the identity of an element?

• The number of electrons.

• The number of neutrons.

• The number of protons.

• The atomic mass.

How can the number of neutrons in an atom be calculated from its mass number and atomic number?

• By adding the atomic number and atomic mass.

• By subtracting the atomic number from the mass number.

• By multiplying the atomic number by the mass number.

• By dividing the mass number by the atomic number.

What is an ion?

• An atom with an equal number of protons and electrons.

• An atom that has gained or lost protons.

• An atom that has gained or lost neutrons.

• An atom that has gained or lost electrons.

What characteristic defines isotopes of an element?

• They have the same number of neutrons but different numbers of protons.

• They have the same number of protons but different numbers of electrons.

• They have the same number of protons but different numbers of neutrons.

• They have different atomic numbers but the same mass number.