Which of the following oxides is most basic?

$Mg$ and $Li$ are similar in their properties due to

On moving from left to right across a period in the periodic table,the metallic character:

Show by a chemical reaction with water that $Na_{2}O$ is a basic oxide and $Cl_{2}O_{7}$ is an acidic oxide.

Consider the elements $N$,$P$,$O$,$S$,$Cl$ and $F$. The number of valence electrons present in the elements with most and least metallic character from the above list is respectively.

Which of the following substances will liberate bromine when reacted with a solution of potassium bromide?