Each period or row in the periodic table and with a what?

The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods.

A mother can give exposure and potentially damage many organs in an embryo by using a harmful substances during the early stages of her pregnancy. It is always important to never take any harmful substances especially if you think you can be pregnant.