Question

To which series will the following elements belong?

${}_{103}^{257}Lr,{}_{99}^{254}Es,{}_{95}^{243}Am.$

Answer 1

${}_{103}^{257}Lr,$ $256$ is divisible by $4$, so $257$ belong to $(4n+1)$ series

${}_{99}^{254}Es,252$ is divisible by $4$, so $254$ belong to $(4n+2)$ series

${}_{95}^{243}Am,340$ is divisible by $4$, so $243$ belong to $(4n+3)$ series