Question

The value of IE1 for He is 2372 kj/mol , the value of IE2 should be

Answer 1

Second ionisation energy of He atom is equal to

$$1st \ ionisation \ energy \ of \ He^+$$

So,

2nd IE of He atom

$$=\frac{ZR_H}{n^2}\\where,\\Z=2\\R_H=2.178×10^{-18}\ J\\n=1$$

We get,

$$2nd \ IE=8.718×10^{-18}\ J\ per\ He^+\ ion$$

$$=8.718×10^{-18}×6.023×10^{23}\\=5247.23\ kJ\ mol^{-1}$$