Question

How do the valence electrons change as you go across a period?

Answer 1

The valence electrons are the electrons in the last shell or energy level of an atom. They do show a repeating or periodic pattern. The valence electrons increase in number as you go across a period. Then when you start the new period, the number drops back down to one and starts increasing again.

Hope this will help you.....

Answer 2

While going from left to right across a period each time a new electron is added to the successive element.

Example:

ELEMENT:                           Na     Mg      Al       Si      P      S     Cl     Ar

VAlENCE ELECTRONS:       1         2        3        4       5       6    7       8

VALENCY:                             1         2         3       4       3        2     1      -