Atomic Structure

Question 1

What are the three sub-atomic particles in atoms?

Answer 1

Protons, neutrons and electrons.

Question 2

What two sub-atomic particles are found in the nucleus?

Answer 2

Protons and neutrons.

Question 3

What happens if an atom loses an electron?

Answer 3

If an atom loses one or more electrons, it becomes a positively charged ion.

Question 4

What happens if an atom gains an electron?

Answer 4

If an atom gains one or more electrons, it becomes a negatively charged ion.

Question 5

What is the atomic number of an atom?

Answer 5

The atomic number of an atom is the number of protons it contains.

Question 6

What is the mass number of an atom?

Answer 6

The mass number of an atom is the total number of protons and neutrons it contains. (The mass number of an atom is never smaller than the atomic number. It can be the same, but is usually bigger.)

Question 7

How do you work out the number of neutrons?

Answer 7

Note that you can work out the number of neutrons by subtracting the atomic number from the mass number. In this example, it is 35 – 17 = 18 neutrons.