The Atom

Question 1

List the 3 subatomic particles in an atom.

Answer 1

• Protons
• Neutrons
• Electrons

Question 2

Give the relative masses and relative charges of a proton, neutron and electron.

Answer 2

Question 3

Describe the structure of an atom, in terms of its subatomic particles.

Answer 3

• Protons and neutrons make up the nucleus
• Electrons orbit the nucleus in electron shells

Question 4

Why is an atom’s nucleus positively charged?

Answer 4

• It is made up of protons and neutrons
• Protons have a positive charge and neutrons do not have a charge

Question 5

Where is most of the mass concentrated in an atom?

Answer 5

The nucleus

Question 6

(Exam-style question)

Use the relative charges of the subatomic particles to explain why an atom has no overall charge.

Answer 6

• Protons have a positive charge, +1, and electrons have a negative charge, -1
• Because atoms have an equal number of protons and electrons, the charges cancel out, therefore atoms have no overall charge

Question 7

How large is the nucleus compared to the overall size of an atom?

Answer 7

Compared to the overall size of an atom, the nucleus is tiny