Atoms And Radiation

Question 1

What is an isotope

Answer 1

Nucleus with the same number of protons but different number of neutrons

Question 2

If an atom loses an electron what does it become?

Answer 2

Positively charged ion

Question 3

If an atom gains an electron what does it become

Answer 3

Negatively charged ion

Question 4

What is the plum pudding model

Answer 4

Atom was imagined to be a sphere of positive charge with negative electrons in it

Question 5

What was Rutherford’s scattering experiment?

Answer 5

Alpha particles were beamed at gold foil.

Scientists thought they would go through the foil

Some came out at different angles and some came straight back

This showered particles were being repelled and deflected

So the plum pudding model was replaced by the nuclear model of the atom

Question 6

What is alpha radiation (4)

Answer 6

Consist of alpha particles
2 protons and 2 neutrons

Atoms that emit alpha radiation are big atoms

After emitting an alpha particles, mass and proton numbers decrease

Question 7

What is beta radiation ? (4)

Answer 7

When a nucleus has too many neutrons

Protons stay in and electrons are emitted as beta particles

Proton number increased by one

Beta consists of high energy electrons

Question 8

What is gamma radiation?

Answer 8

No protons or neutrons emitted

Only excess energy is emitted

Short wavelength high frequency

Question 9

How good are the 3 types of radiation at penetrating

Answer 9

Alpha- least penetrating

Beta - penetrate air and paper

Gamma - most penetrating

Question 10

What can beta radiation be stopped by?

Answer 10

Thin sheet of aluminium

Question 11

What is half life?

Answer 11

Time taken for the count rate of a sample to halve

Question 12

What does a short half life mean

Answer 12

Small amount of time a nucleus takes to decay

Question 13

How does an atom became stable

Answer 13

Emit gamma radiation or particles

Question 14

WHERE are each of the three types of radiation used?

Answer 14

Alpha - smoke alarms
Beta - paper thickness
Gamma - cancer treatment

Question 15

What is a good property of alpha?

Answer 15

Great ionisation power

Question 16

What are the charges of the 3 forms of radiation

Answer 16

Alpha +2
Beta -1
Gamma no charge

Question 17

Why is alpha the most dangerous to have. In your body

Answer 17

It is easily absorbed by cells. Beta and gamma just pass through

Question 18

Why are beta and gamma more dangerous outside of the body

Answer 18

It can penetrate skin and damage cells inside

Question 19

What happens when alpha particles decay?

Answer 19

Two neutrons and protons are lost so
Atomic mass decreases by 4
Atomic number decreases by 2

Question 20

What is fission

Answer 20

Spilt ting up larger atomic nucleus into 2 smaller nuclei

Question 21

What are the 4 things that happen in fission

Answer 21

Nucleus splits into 2 smaller nuclei

Two or 3 neutrons are released

Some energy is released

The neutrons that have split split again so reaction continues

Question 22

Advantages and disadvantages of fission

Answer 22

More energy per kg of fuel

Radioactive waste

Question 23

What is fusion

Answer 23

When two atomic nuclei join to make a large nucleus

Question 24

What conditions do you need for fusion

Answer 24

Lots of heat and pressure (from sun)

Question 25

What happens in fusion

Answer 25

Nuclei with the same charge struggle to fuses as they repel

Heat and pressure from the sun fuses them together

Question 26

Why is fusion safer

Answer 26

They leave few radioactive products when worn out

They don’t become dangerous if anything fails