Isotopes (SSC CGL, CHSL etc,)

Any of two or  more forms of an element having same atomic number but different mass number.

Isotopes have same number of protons.

Isotopes of Hydrogen are
1. Protium (1H1)
2. Dutirium (1H2)
3. Tritium (1H3)
Tritium is the lightest radioactive elements.

Carbon Isotopes

6 C 12,
6 C 14

Uranium 235 and Uranium 239