P7 - Radioactivity

Question 1

Alpha particle

Answer 1

A positively charged particle consisting of two protons and two
neutrons.

Question 2

Atomic number

Answer 2

The number of protons found in an atom of a specific element. Each element has a different atomic number

Question 3

Background radiation

Answer 3

Radiation that is found in small quantities all around us and originates from natural sources such as rocks and cosmic rays, as well as from man-made sources such as nuclear weapons testing and accide

Question 4

Becquerel

Answer 4

The unit of radioactive activity

Question 5

Beta particle

Answer 5

A high speed electron that a nucleus emits when a neutron
converts into a proton.

Question 6

Bohr model

Answer 6

A model of the atom that suggested that electrons orbit the nucleus at set distances.

Question 7

Chain reaction

Answer 7

The process of neutrons released by a fission reaction, being absorbed by another unstable, large nuclei, and inducing further fission.

Question 8

Energy levels

Answer 8

The stable states in which electrons are found in around a nucleus. Electrons can transition to a higher energy level through the absorption of electromagnetic radiation and can transition to a lower energy level through the emission of electromagnetic radiation.

Question 9

Fission products

Answer 9

Fission produces two smaller nuclei, two or three neutrons and gamma rays. All these products are released with kinetic energy

Question 10

Gamma ray

Answer 10

Electromagnetic radiation emitted from a nucleus.

Question 11

Geiger-Muller tube

Answer 11

A detector that measures the count-rate of a radioactive sample.

Question 12

Half life

Answer 12

The time it takes for the number of unstable nuclei of an isotope in a sample to halve, or the time it takes for the initial count rate of a sample of the isotope to halve.

Question 13

Ions

Answer 13

Atoms with a resultant charge due to the loss or gain of electrons.

Question 14

Irradiation

Answer 14

The process of an object being exposed to nuclear radiation. The object doesn’t become radioactive.

Question 15

Isotopes

Answer 15

Atoms with the same number of protons but different numbers of neutrons. The atomic number is the same, but the mass number is different.

Question 16

Mass number

Answer 16

The number of protons and neutrons in an atom.

Question 17

Nuclear explosions

Answer 17

Nuclear explosions in nuclear weapons are caused by an uncontrolled chain reaction which results in vast quantities of energy being produced in a very small period of time.

Question 18

Nuclear fission

Answer 18

The splitting of a large and unstable nucleus into two smaller and more stable nuclei to produce energy.

Question 19

Nuclear fusion

Answer 19

The joining of two small, light nuclei to form a larger, heavier one and release energy.

Question 20

Nucleus

Answer 20

The positively charged centre of an atom, containing protons and neutrons.

Question 21

Plum pudding model

Answer 21

An old model of the atom that represented the atom as a ball of positive charge, with negative charges distributed throughout it.

Question 22

Radioactive contamination

Answer 22

The unwanted presence of radioactive atoms on other materials. It is hazardous due to the decay of the contaminating atoms.

Question 23

Radioactive decay

Answer 23

The random process involving unstable nuclei emitting radiation to become more stable.

Question 24

Sieverts

Answer 24

The unit used for radiation dosage.

Question 25

Spontaneous fission

Answer 25

Fission that occurs without the absorption of a neutron.
Spontaneous fission is rare and in most cases, fission is induced with a neutron.