Radioactivity and atomic structure

Question 1

describe alpha radiation

Answer 1

alpha particles each composed of two protons and two neutrons emitted by unstable nuclei

Question 2

what is the atomic number

Answer 2

the number of protons in an atom

Question 3

what is beta radiation?

Answer 3

beta particles that are high energy electrons created in and emitted from unstable nuclei

Question 4

what is the count rate?

Answer 4

the number of counts per second detected by a Geiger counter

Question 5

what is gamma radiation?

Answer 5

electromagnetic radiation is emitted from unstable nuclei in radioactive substances

Question 6

what is half-life?

Answer 6

the average time taken for the number of nuclei of the isotope in a sample to halve

Question 7

what is ionisation?

Answer 7

any process in which atoms become changed

Question 8

what is the mass number?

Answer 8

the number of proton and neutron in the nucleus

Question 9

where are the protons and neutrons located?

Answer 9

in the nucleus

Question 10

where are the electrons located?

Answer 10

in the shells

Question 11

what is the mass of a proton?

Answer 11

1

Question 12

what is the mass of a neutron?

Answer 12

1

Question 13

what is the mass of an electron?

Answer 13

very small

Question 14

what is alpha stopped by?

Answer 14

a few sheets of paper

Question 15

what is beta stopped by?

Answer 15

penetrate paper but stopped by a thin sheet of aluminium

Question 16

what is gamma stopped by?

Answer 16

lead or several metres of concrete

Question 17

what’s the slowest type of radiation?

Answer 17

alpha then beta then gamma

Question 18

which type of radiation has the highest ionising power?

Answer 18

alpha then beta then gamma

Question 19

what are isotopes?

Answer 19

elements with different atomic masses, they have a different number of neutrons

Question 20

describe the plum pudding model

Answer 20

is suggested the atom is a ball of positive charge with negative electrons embedded in it