Atomic structure and radioactivity

Question 1

Atom radius

Answer 1

1 × 10(-10) metres.

Question 2

mass number

Answer 2

number on top
protons and neutrons

Question 3

atomic number

Answer 3

number on bottom
protons

Question 4

isotopes

Answer 4

same element but with different number of neutrons

Question 5

plum pudding model

Answer 5

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

Question 6

alpha particle scattering experiment

Answer 6

the discovery of the nucleus and the nuclear model

Question 7

Bohr’s model

Answer 7

electrons orbit the nuclues at certain lengths

Question 8

Chadwick’s model

Answer 8

nuetrons in the nuclues

Question 9

radioactive decay

Answer 9

a random process in which the nucleus gives out radiation to become more stable

Question 10

activity

Answer 10

the rate at which a source of unstable nuclei decays

mesaured in Becquerel

Question 11

alpha particle

Answer 11

2 neutrons and 2 protons

same as helium nucleus

Question 12

beta particle

Answer 12

high speed electron ejected from nucleus as a nuetron which turns into a proton

Question 13

gamma ray

Answer 13

electromagnetic radiation from the nucleus

does not cause the mass or the charge to change

Question 14

nuclear equations

alpha symbol

Answer 14

4
2He

causes mass and charge to decrease

Question 15

nuclear euations

beta symbol

Answer 15

0
-1 e

does not change the mass of the nucleus

Question 16

half-life

Answer 16

the time it takes for the number of nuclei to halve
or the time it takes for the count-rate to halve

Question 17

radio contamination

Answer 17

unwanted presence of materials containing radioactive atoms on other materials

Question 18

irradation

Answer 18

process of exposing an object to nuclear radiation

does not become radioactive