Question

Choose from the following:
${}_{6}C,{}_{8}O,{}_{10}Ne,{}_{11}Na,{}_{14}Si$
(i) Elements that should be in the same period
(ii) Elements that should be in the same group
State reason for your selection in each case:

Answer 1

1. ${}_{6}C,{}_{8}O$ and ${}_{10}Ne$ all belong to period 2 as they have two shells whereas ${}_{11}Na$ and ${}_{14}Si$ belong to period 3 as they have 3 shells.

2. ${}_{6}C$ and ${}_{14}Si$ belong to the same group 14 since they have same number of valence electrons.