Which one among the following statements is/are not correct?
$I$. $Ba$ compounds,generally are more covalent than $Be$ compounds.
$II$. The electron gain enthalpy of $He$ is positive.
$III$. The oxidation state of $O$ in $OF_2$ and $Na_2O$ are same.
$IV$. The radius of $Na^{+}$ ion is smaller than that of $F^{-}$ ion.

Identify the correct statements from the following.
$(i)$ In the periodic table,about $78 \%$ of elements are metals.
$(ii)$ In a group,the metallic character decreases from top to bottom and in a period the nonmetallic character decreases from left to right.
$(iii)$ The element $Ho$ belongs to $f-$block.

Which of the following statements are not correct?
$A.$ The electron gain enthalpy of $F$ is more negative than that of $Cl$.
$B.$ Ionization enthalpy decreases in a group of the periodic table.
$C.$ The electronegativity of an atom depends upon the atoms bonded to it.
$D.$ $Al_2O_3$ and $NO$ are examples of amphoteric oxides.
Choose the most appropriate answer from the options given below:

Choose the correct option regarding the following statements:
Statement-$1$: Nitrogen has lesser electron gain enthalpy than oxygen.
Statement-$2$: Oxygen has lesser ionization enthalpy than nitrogen.

Match List – $I$ with List – $II$

List – $I$ (Element, Atomic number)	List – $II$ (Position in periodic table)
$(a)$ $Ra$ – $88$	$(i)$ $4^{th}$ period, $13^{th}$ group
$(b)$ $Ga$ – $31$	(ii) $6^{th}$ period, $6^{th}$ group
$(c)$ $W$ – $74$	(iii) $5^{th}$ period, $10^{th}$ group
$(d)$ $Pd$ – $46$	(iv) $7^{th}$ period, $2^{nd}$ group

Which elements in groups $1$ to $17$ differ in many respects from the other elements of their respective groups?