Which of the following sets is incorrect?

Observe the following statements:
$I$. The physical and chemical properties of elements are periodic functions of their electronic configuration.
$II$. Electronegativity of fluorine is less than the electronegativity of chlorine.
$III$. Electropositive nature decreases from top to bottom in a group.
The correct answer is:

The cause of the diagonal relationship is:

Fluorine,chlorine,bromine and iodine are placed in the same group $(17)$ of the periodic table,because

Select the correct statements from the following:
$(a)$ Effective nuclear charge for nitrogen is $3.90$
$(b)$ $IP$ of $Ne$ is more than $Na^{+}$
$(c)$ Order of electronegativity $sp > sp^2 > sp^3$
$(d)$ Order of acidic character $NH_3 < PH_3 < AsH_3$

Compare the ionization enthalpy and electron gain enthalpy values of the elements given below:

Element Description	Element	$\Delta_{i}H_1$	$\Delta_{i}H_2$	$\Delta_{eg}H$
$(i)$ Most reactive non-metal	$(A)$	$419$	$3051$	$-48$
$(ii)$ Most reactive metal	$(B)$	$1681$	$3374$	$-328$
$(iii)$ Least reactive element	$(C)$	$738$	$1451$	$-40$
$(iv)$ Metal forming dihalide	$(D)$	$2372$	$5251$	$+48$