A level Physics- Particles and Radiation

,am Particles
January 2022



The number of protons in an atom is known as the atomic number a


proton number and is represented
by
the
Symbol 2 ,
which
defines
the element which the
to atom
belongs .
to




A neutral atom =
same number of elections as protons .




A nucleou is a proton(neutron ,
so the nucleon number
of an arow

is the number
of protons + neutrons in the nucleus
.



It represented A the
is
by
the
Symbol ,
known as mass number
.




nucleon
-
number (2) 0

Ca
20
Proton
number -
(2)

Number
of neutrons = nucleor - proton
number .
number




charges

Relative
charges chargeinsa
Electron -
I
e
-
1 .
60x10 - 9C Elementary
:
,
charge
-




19(
+




e =
1 .

60 x 10

Proton + 1
2
+ 1 60 x 10-1 C
+
.




,

, Specific Charge
Ispecific charge is
Marge
-
per unit mass
for a particle :




becific
charge
Not in data
charge
~
= onis




units : Coulombs por
kilogram
-



Chgt
H
can
-
De calculated
for particle :




Proton
10 58x10Chg"
=

= 9 .




z




significant
figures
To is considered te
a
of
the massed
· 3 protons a b

neutrons
-




The same
-
~




The mass
of the electrons is
negligible compared to the proton
·



and neutron ,
and can be .
ignored
If using this in exam ,
WRITE This STATEMENT



-Treific
-




· When asked to compare
-
-
charges ,
calculate
using relative

and numbers
charges
-
nucleon
-
.