Question

what is the difference between a period and a group on the periodic table

Answer 1

A period is the colums goi
ng down on the periodic table, and the groups are the rows going across

Answer 2

Periods go left to right in a straight line.  Anything in the same ROW is a Period.
Groups are up to down.  These groups have the same number of outer shell electrons.  There are 12 groups.