What do “groups” and “periods” mean on a periodic table of elements?
Groups or families are the columns on the periodic table. Periods are the rows of the periodic table. “Wait…this is important, I don’t know what ‘rows’ and ‘columns’ mean!” Rows are horizontal collections of cells of a table Columns are vertical collections of cells of a table This distinction between ‘rows’ and ‘columns’ is ALWAYS true. Think vertical when thinking of columns, and think horizontal when thinking of rows. Remember also, “vertical row” is an oxymoron. Significance to chemistry, families of elements are elements with similar properties and similar behavior. Elements of the same period usually aren’t related, they are just nearby in atomic number or atomic mass.
