Answer:
The horizontal rows are called period.
The vertical column are called groups.
Step-by-step explanation:
Periodic table consist of eighteen groups and seven periods.
The horizontal rows are called period.
The vertical column are called groups.
The elements are arranged in specific pattern.
The element in same group have similar properties.
As moving down the group atomic sizes increases with increase of atomic number.
Along period left to right atomic sizes decreases with increase of atomic number.
The number of group indicate the valance electrons of elements present in respective group. e.g
Sodium is present in group one it has one valance electron.
Chlorine is present 7-A have seven valance electrons.
Periodic table is also divided into four blocks s,p d and f.
The s block elements have valance electrons in s orbital, P-block elements have valance electrons in p orbital, f- block elements have valance electrons in f orbital and d-block elements in d-orbital.