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)
	I1	I2	I3
n	1681	3374	6050
n+1	2081	3952	6122
n+2	469	4562	6910
n+3	738	1451	7733

Answer 1

Correct Answer: 9

Since I.E. of Na is 495.8 kJ mol^–1 , so (n + 2) should be 11.
 n + 2 = 11, So n = 9