In a period from $Li$ to $F$,ionization potential

Which of the following elements are at the peaks of the ionization energy trend?

Which of the following isoelectronic series would lose an electron most easily?

The $1^{\text{st}}$,$2^{\text{nd}}$,and $3^{\text{rd}}$ ionization enthalpies $I_1, I_2$,and $I_3$ of four atoms with atomic numbers $n, n+1, n+2$,and $n+3$,where $n < 10$,are tabulated below. What is the value of $n$?

Atomic number	$I_1$ $(kJ/mol)$	$I_2$ $(kJ/mol)$	$I_3$ $(kJ/mol)$
$n$	$I_1$	$I_2$	$I_3$
$n+1$	$1681$	$3374$	$6050$
$n+2$	$2081$	$3952$	$6122$
$n+3$	$496$	$4562$	$6910$
$n+4$	$738$	$1451$	$7733$

What will be the order of $1^{st}$ ionisation energy for the alkali metals $Li$,$Na$,and $K$?

The correct order of the second ionization energy of $C$,$N$,$O$,and $F$ is :-