Chapter U1.18, Problem 5E

Interpretation Introduction

Interpretation:

For main group elements, the change in core elements across the period needs to be explained.

Concept introduction:

Core electrons are those which are in the innermost orbit and do not participate in the chemical reaction.

Answer to Problem 5E

Across a period number, number of core electrons remains the same for main group elements.

Explanation of Solution

While going across a period from left to right, the number of valence electrons increases but number of core electrons remains same.

For example from Li to Ne, the number of core electrons is 2 but valence electrons changes from 1 to 8.

Conclusion

Core electrons remains same across a period.