Chapter 6, Problem 67A

Interpretation Introduction

Interpretation:

The number of valence electrons in element of group 1 and group 18 needs to be determined.

Concept introduction:

Electrons present in its outermost shell of an element are termed as valence electrons. The valence electrons participate in bond formation and determines the number of bonds an element can form.

Answer to Problem 67A

Elements of group 1 has one valence electron and the elements of group 18 have eight valence electrons.

Explanation of Solution

The number of valence electrons in an element is equal to the group number. Hence, elements of group 1 like H, Li, Na, K, Rb, Cs and Fr have one valence electrons.

Group 18 consists of noble gases like He (1s²), Ne ( [He] 2s² 2p⁶ ), Ar ( [Ne] 3s² 3p⁶) etc. have eight valence electrons.

Conclusion

Group 1 elements like H, Li, Na, K, Rb, Cs and Fr have one valence electrons and Group 18 elements like He, Ne, Ar, Kr, Xe and Rn has eight valence electrons.