describe what the periods and groups on the periodic table are, how they are different, and what they tell us about an atoms structure.

Explanation:

Periods and groups describes the arrangement of elements on the periodic table using the atomic number of each of the given elements.

Elements in the same period have the same number of energy levels or electronic shell.

The period of an element is an indicator of the energy levels in an atom. The groups precisely tells us the number of valence electrons in the atom.

i do not get it   at all