Radioactivity

Question 1

Describe alpha decay and alpha particles.

Answer 1

An alpha particle consists of two protons and two neutrons. (It is the same as a helium nucleus). When a atom nucleus decays and releases an alpha particle, it loses two protons and two neutrons

• Mass number decreases by 4
• atomic number decreases by 2

The number of protons has changed so the element has changed into a new one.

Question 2

Describe beta radiation and beta particles.

Answer 2

An beta particle consists of a high energy electron, which is emitted by the nucleus of the decaying atom.
When an atom’s nucleus decays and releases a beta particle, a neutron turns into a proton, which stays in the nucleus, and a high energy electron, which is emitted.

• Mass number remains the same
• Atomic number increases by 1

The decayed atom has gained a proton and so has changed into a new element.

Question 3

Describe gamma radiation and gamma particles.

Answer 3

Gamma radiation is a form of electromagnetic radiation, not a type of particle.

When an atom’s nucleus decays and emits gamma radiation, it releases energy in the form of electromagnetic radiation.
There is no change to the make up of the nucleus and so a new element is not formed.

Gamma rays are usually emitted with alpha or beta particles. For example, cobalt-60 decays releasing a beta particle. The nickel formed is still not stable and so emits gamma radiation.

Question 4

For alpha particles what is the symbol, charge, mass, speed, range(percentage power), ionising power, what is it stopped by and is it affected by a magnetic field.

Answer 4

symbol: α,
charge: 2+,
mass: 4,
speed: slow,
range(percentage power): weak(5cm),
ionising power: strongly ionising,
what is it stopped by: paper
is it affected by a magnetic field: the most

Question 5

For beta particles what is the symbol, charge, mass, speed, range(percentage power), ionising power, what is it stopped by and is it affected by a magnetic field.

Answer 5

symbol: β,
charge: -,
mass: 1/2000,
speed: medium speed,
range(percentage power): medium(15cm),
ionising power: quite ionising,
what is it stopped by: aluminium
is it affected by a magnetic field: a bit

Question 6

For gamma particles what is the symbol, charge, mass, speed, range(percentage power), ionising power, what is it stopped by and is it affected by a magnetic field.

Answer 6

symbol: γ,
charge: no charge,
mass: 0,
speed: very fast,
range(percentage power): (few meters),
ionising power: weakly ionising,
what is it stopped by: few inches of lead
is it affected by a magnetic field: no affect

Question 7

How do you calculate atomic mass?

Answer 7

The number of protons + the number of neutrons.

Question 8

What is an isotope?

Answer 8

An element with the same atomic number but a different number of neutrons.

Question 9

What is half life?

Answer 9

The time take for a radioactive substance to lose half of its radioactive particles to decay

Question 10

What does uranium decay into to become stable?

Answer 10

Uranium 238, thorium 234, protactinium 234, uranium 234, thorium 230, radium 226, radon 222, polonium 218, lead 214, Bismuth 214, Polonium214, Lead 210, Bismuth 210, Polonium 210, lead 206(stable)

Question 11

What is radiation?

Answer 11

Radiation is a unstable nucleus emitting energy such as gamma, beta or alpha to be become stable