Question

There is a gradual decrease in size of atoms or $M^{+3}$ ions across the actinide series

• A. True
• B. False

Answer 1

The correct option is A True

Ionic size gradually decreases from $A{c}^{+3}$ to $L{r}^{+3}$, this is called actinide contraction, which is a result of poor or ineffective shielding by 5f electrons. These electrons do not screen the outermost valence electrons which experience a greater electrostatic attraction from the positively charged nucleus.