(a) (i) The vertical column of the periodic table is known as a group.
(ii) The horizontal row of elements in a periodic table is known as a period.
(b) In total, there are seven periods and eighteen groups in the long form of the periodic table.
(a) (i) The vertical column of the periodic table is known as a group.
(ii) The horizontal row of elements in a periodic table is known as a period.
(b) In total, there are seven periods and eighteen groups in the long form of the periodic table.