Isotopes

Isotopes are atoms of certain elements which have the same number of protons but different number of neutrons in the nucleus of the atoms.

It can also be defined as atoms of certain elements with the same proton numbers but with different nucleon numbers.

Properties of Isotope
Number of proton equal
Number of neutron difference
Chemical properties same
Physical properties difference

Example:
Element Name Symbol Proton Number Nucleon Number Number of proton Number of neutron
Hydrogen Hydrogen
11H
1
1
1
0
Deuterium
21H
1
12
1
1
Tritium
31H
1
23
1
2
Oxygen Oxygen-16
168O
8
16
8
8
Oxygen-17
178O
8
17
8
9
Oxygen-18
188O
8
18
8
10
Carbon Carbon-12
126C
6
12
6
6
Carbon-13
136C
6
13
6
7
Carbon-14
146C
6
14
6
8
Chlorine Chlorine-35
3517Cl
17
35
17
18
Chlorine-37
3717Cl
17
37
17
20
Sodium Sodium-23
2311Na
11
23
11
12
Sodium-24
2411Na
11
24
11
13