Question

The $1^{\text{st }},2^{\text{nd }}$, and the $3^{\text{rd }}$ 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	Ionization Enthalpy (kJ/mol)
	$I_1$	$I_2$	$I_3$
n	1681	3374	6050
n + 1	2081	3952	6122
n + 2	496	4562	6910
n + 3	738	1451	7733

Answer 1

Answer: 9

Since I.E. of $Na$ is $495.8kJmo{l}^{-1}$,
so $(n+2)$ should be $11$ .
$n+2=11$, So $n=9$