Question

The first four ionization energy values of an element are 191, 578, 872 and 5962 Kcal. the number of valency electrons in the element is

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

The correct option is C $3$

Since there is high energy difference between third ionization and fourth ionization. It means higher amount of energy is required to remove the fourth electron. It indicates element has attained stable configuration after removal of 3rd electron. So number of valence electrons in the element is 3.