The vertical rows in the periodic table are called __________.

The vertical columns of the periodic table are called groups. There are 18 groups in the periodic table. The elements in a group have the same number of valence electrons. 

The horizontal rows are referred to as periods. There are 7 periods in a periodic table. Period 1 has only two elements, while periods 2 and 3 have 8 elements. Periods 4 and 5 have 18 elements. Periods 6 and 7 have 32 elements.