Atomic Structure

Question 1

What are the three main subatomic particles?

Answer 1

Protons, neutrons, and electrons.

Question 2

What is the relative charge of a proton?

Answer 2

1

Question 3

What is the relative charge of a neutron?

Answer 3

0 (neutral)

Question 4

What is the relative charge of an electron?

Answer 4

-1

Question 5

Where are protons and neutrons found?

Answer 5

In the nucleus of an atom.

Question 6

Where are electrons found?

Answer 6

In shells (energy levels) orbiting the nucleus.

Question 7

What is the atomic number of an element?

Answer 7

The number of protons in the nucleus.

Question 8

What is the mass number of an atom?

Answer 8

The total number of protons and neutrons.

Question 9

What are isotopes?

Answer 9

Atoms of the same element with the same number of protons but different numbers of neutrons.

Question 10

What is radioactive decay?

Answer 10

The spontaneous breakdown of an unstable atomic nucleus, releasing radiation.

Question 11

What is activity measured in?

Answer 11

Becquerels (Bq) – 1 Bq = 1 decay per second.

Question 12

What is a half-life?

Answer 12

The time it takes for the number of radioactive nuclei (or activity) to halve.

Question 13

Name three types of nuclear radiation.

Answer 13

Alpha (α), Beta (β), and Gamma (γ) radiation.

Question 14

What is alpha radiation?

Answer 14

A particle made of 2 protons and 2 neutrons – same as a helium nucleus.

Question 15

What is beta radiation?

Answer 15

A high-speed electron emitted from the nucleus when a neutron turns into a proton.

Question 16

What is gamma radiation?

Answer 16

An electromagnetic wave released from the nucleus with no mass or charge.

Question 17

Which type of radiation is most ionising?

Answer 17

Alpha radiation.

Question 18

Which type of radiation is least penetrating?

Answer 18

Alpha – stopped by paper or skin.

Question 19

Which radiation can be stopped by aluminium?

Answer 19

Beta radiation.

Question 20

Which radiation can penetrate thick lead or concrete?

Answer 20

Gamma radiation.

Question 21

What does ionising mean?

Answer 21

The ability to knock electrons off atoms, turning them into ions.

Question 22

Give one use of gamma radiation.

Answer 22

Used in medical tracers and cancer treatment (radiotherapy).

Question 23

Give one use of beta radiation.

Answer 23

Used in thickness control in industries (e.g. paper or foil production).

Question 24

Give one use of alpha radiation.

Answer 24

Used in smoke detectors.

Question 25

Why is alpha radiation dangerous inside the body?

Answer 25

Because it is highly ionising and causes damage to nearby cells.

Question 26

Why is gamma radiation dangerous outside the body?

Answer 26

Because it can penetrate deep into the body and damage internal organs.

Question 27

What is background radiation?

Answer 27

Low-level radiation that is always present from natural and artificial sources.

Question 28

Give three sources of background radiation.

Answer 28

Cosmic rays, rocks and soil (e.g. radon gas), and medical sources.

Question 29

How can we reduce irradiation?

Answer 29

Using lead shielding, keeping distance, and reducing exposure time.

Question 30

What is contamination?

Answer 30

When radioactive material is on or in an object or person.

Question 31

How can we reduce contamination?

Answer 31

Using gloves, tongs, protective suits, and following safety procedures.

Question 32

What is irradiation?

Answer 32

Being exposed to radiation without coming into contact with the source.

Question 33

Can an irradiated object become radioactive?

Answer 33

No, irradiation does not make objects radioactive.

Question 34

What are the risks of radiation exposure?

Answer 34

Can cause cell damage, mutations, cancer, and radiation sickness.

Question 35

Why are long half-life isotopes dangerous?

Answer 35

They emit radiation for a long time, increasing long-term exposure risk.

Question 36

Why are short half-life isotopes useful in medicine?

Answer 36

They deliver radiation quickly and decay before causing long-term harm.

Question 37

What happens to atomic number and mass in alpha decay?

Answer 37

Atomic number decreases by 2, mass number decreases by 4.

Question 38

What happens to atomic number and mass in beta decay?

Answer 38

Atomic number increases by 1, mass number stays the same.

Question 39

What happens to atomic number and mass in gamma emission?

Answer 39

No change in atomic number or mass number.

Question 40

What is nuclear fission?

Answer 40

The splitting of a large atomic nucleus into smaller nuclei, releasing energy.

Question 41

What is nuclear fusion?

Answer 41

The joining of two light atomic nuclei to form a heavier nucleus, releasing energy.

Question 42

Where does fusion occur naturally?

Answer 42

In the cores of stars, including the Sun.

Question 43

Why is fusion difficult to achieve on Earth?

Answer 43

It requires extremely high temperatures and pressures.

Question 44

Why are neutrons important in fission reactions?

Answer 44

They initiate the chain reaction by causing further fissions.

Question 45

Why is nuclear fusion considered 'clean'?

Answer 45

It produces no radioactive waste and uses abundant fuel (hydrogen).