Question

How does the number of valence electrons for elements change across a period?

The number decreases.

The number increases.

The number stays constant.

The number increases and then decreases for noble gases

Answer 1

D. The number increases and then decreases for noble gases

Answer 2

Answer: Option (b) is the correct answer.

Step-by-step explanation:

Valence electrons is the number of electrons present in the outermost shell of an atom.

So, when we move across a period from left to right then there will be increase in number of valence electrons.

For example, valence electrons in carbon is 4, nitrogen has 5 valence electrons, oxygen has 6 valence electrons.

Thus, we can conclude that number of valence electrons increases for elements change across a period.