Question

When moving across a period from left to right in the periodic table (excluding transition elements) which trend occurs?(1 point)
Responses

The energy levels increase by one.
The energy levels increase by one.

The energy levels decrease by one.
The energy levels decrease by one.

Valence electrons decrease by one.
Valence electrons decrease by one.

Valence electrons increase by one.

Answer 1

When moving across a period from left to right in the periodic table (excluding transition elements), the trend that occurs is:

**Valence electrons increase by one.**

As you move from left to right, each element gains an additional valence electron, which is consistent across the main group elements.