Which of the following orders is $CORRECT$?

Which element from the following exhibits a diagonal relationship with $Mg$?

Match the Column $I$ with Column $II$ and select the correct answer using the given codes.

Column $I$ (Element types)	Column $II$ (Electronic configuration)
$A$. Inert-gas elements	$1. (n-1)d^{1-10} ns^{1-2}$
$B$. Transition elements	$2. ns^2 np^6$
$C$. Inner-transition elements	$3. (n-2)f^{1-14} (n-1)s^2 p^6 d^{0-1} ns^2$

Which of the following statements are correct?
$A.$ The process of the addition of an electron to a neutral gaseous atom is always exothermic.
$B.$ The process of removing an electron from an isolated gaseous atom is always endothermic.
$C.$ The $1^{st}$ ionization energy of boron is less than that of beryllium.
$D.$ The electronegativity of $C$ is $2.5$ in $CH_4$ and $CCl_4$.
$E.$ $Li$ is the most electropositive among elements of group $I$.
Choose the correct answer from the options given below:

Identify the incorrect order.

The electronic configurations of $4$ atoms are given below:
$P = [Ne] \, 3s^2 3p^3$
$Q = [Ar] \, 3d^{10} 4s^2 4p^3$
$R = [He] \, 2s^2 2p^5$
$S = [Ne] \, 3s^1$
Which of the following statements is incorrect?