unit 11 - atoms and radioactivity

Question 1

what is an ionizing effect

Answer 1

the nuclear radiation removing electrons from atoms in its path

Question 2

feature of alpha particle

Answer 2

identical to the helium atom
relative charge of 2
relatively high mass
1/10 of speed of light 
high ionizing effect
not very penetrating, can be stopped by a paper
it can be deflected by electric fields

Question 3

feature of beta particle

Answer 3

identical to the electron
relative charge of -1
relatively less mass 
9/10 of speed of light 
low ionizing effect
penetrating but it can be stop by aluminium 
it can be deflected by electric fields

Question 4

feature of gamma rays

Answer 4

electromagnetic waves
relative charge of 0 
no mass
speed of light 
weak ionizing effect
very penetrating but it can be stop by lead
not deflected by electric field

Question 5

why does alpha particle have greater ionizing effect than beta particle and gamma doesn’t have ionizing effect

Answer 5

greater charge

gamma rays are uncharged

Question 6

how can the direction of the alpha and beta particle can be determined when it crosses the magnetic field

Answer 6

Flemming left hand rule for alpha

opposite direction for beta

Question 7

what is alpha decay

Answer 7

atom loses 2 neutrons and 2 protons + alpha particle

Question 8

what is beta decay

Answer 8

atom gains proton + beta particle

Question 9

what is a half life

Answer 9

the time taken for the activity of any given sample to fall to half its original value

Question 10

use of radioactivity

Answer 10

detecting leaks, checking the function of body organs

Question 11

what happens to the alpha particle as it goes through gold foil

Answer 11

most alpha particle are undeflected because most of the gold particle are empty space

a few alpha particle are slightly deflected because the same charges repel each other

a few alpha particle bounce off the nucleus so it is largely deflected