(III) The Uranium Series: This series begins with 
and ends with
. The mass numbers (sum of neutrons and protons numbers) in the series are given by 4 n +2, where, n is an integer. That is way this series is known as 4 n + 2 series.
The Uranium Series (4 n + 2)
(IV) The Actinium Series: This series begins with 
and ends with
The mass numbers (sum of neutrons and protons numbers) in the series are given by 4 n + 3, where, n is an integer. That is way this series is known as 4 n + 3 series.
The Actinium Series (4 n + 3)
