Match the following elements with their respective blocks in the periodic table based on their atomic number $(Z)$:

Column-$I$	Column-$II$
$A. Z = 37$	$P. p-$ block
$B. Z = 42$	$Q. f-$ block
$C. Z = 34$	$R. d-$ block
$D. Z = 92$	$S. s-$ block

Which of the following statements are correct?
$(i)$ First ionisation enthalpy of $He < $ Second ionisation enthalpy of $Li$.
$(ii)$ $Li$ has the highest second ionisation enthalpy.
$(iii)$ All $d$-block elements are transition elements.
$(iv)$ The only alphabet not found in the periodic table is the letter '$J$'.
$(v)$ Francium concentration is $\sim 10^{-18} \ ppm$ on Earth.

Two statements are given below.
Statement $I$: Nitrogen has more ionization enthalpy and electronegativity than beryllium.
Statement $II$: $CrO_3$ and $B_2O_3$ are acidic oxides.
Correct answer is

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

Maximum number of electrons in the outermost shell of $s, p, d$,and $f$ block elements are respectively:

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.