Structure of the atom

Question 1

Proton

Answer 1

A tiny positive particle found inside the nucleus of an atom.

Question 2

Neutron

Answer 2

A dense particle found in the nucleus of an atom. It is electrically neutral, carrying no charge.

Question 3

Electron

Answer 3

A tiny particle with a negative charge. Electrons orbit the nucleus of atoms or ions in shells.

Question 4

Atomic number

Answer 4

The number of protons (which equals the number of electrons) in an atom. It is sometimes called the proton number.

Question 5

Mass number

Answer 5

The number of protons plus neutrons in the nucleus of an atom.