Assertion : Thorium, uranium and actinium series are designated as 4n, 4n+2 and 4n+3 series respectively. Reason : The mass number of all elements in the thorium series are divided by 4 gives a remainder of 2 while those of actinium series gives a remainder of 3 when the mass number is divided by 4.

Assertion : Thorium, uranium and actinium series are designated as 4n,

1.	Assertion : Thorium, uranium and actinium series are designated as 4n, 4n+2 and 4n+3 series respectively. Reason : The mass number of all elements in the thorium series are divided by 4 gives a remainder of 2 while those of actinium series gives a remainder of 3 when the mass number is divided by 4.
Answer» Both A and R are TRUE and R is the correct explanation of A Both A and R are true but R is not a correct explanation of A A is true but R is FALSE A is false but R is true Answer :A