Which of the following is a false statement?

Explain the following:
$(a)$ Electronegativity of elements increases on moving from left to right in the periodic table.
$(b)$ Ionisation enthalpy decreases in a group from top to bottom.

Match the following and select the correct option:

List-$I$	List-$II$
$(A)$ Ionization enthalpy	$(i)$ $P < Si < Mg < Na$
$(B)$ Metallic character	$(ii)$ $I < N < O < F$
$(C)$ Electron gain enthalpy	$(iii)$ $B < Be < C < O < N$
$(D)$ Electronegativity	$(iv)$ $I < Br < F < Cl$

Which of the following properties does not depend on periodicity?

Which of the following set of properties generally decreases along a period?

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.