Question

What is the meaning of halogens?

Answer 1

Halogens are the chemical elements that can be used for the formation of salts with metals. Thus, the halogens are the salt forming elements. The valence of halogens is $7$ and there is a deficit of only one electron to attain inert or noble gas configuration.

Complete answer:
Periodic table is the representation of chemical elements arranged in the increasing order of atomic numbers arranged in the vertical columns and horizontal rows. These vertical columns are called groups and the horizontal rows are called periods. There are a total of $7$ periods and $18$ groups.
The elements belonging to $17$ group are called halogens.
Halogens are five elements.
In the Greek language, halo means salt and gen means formation which gives the meaning of salt formation.
Thus, Halogens are considered as salt formers.
When halogens react with metals to form salt.
The elements of halogens are fluorine, Chlorine, Bromine, Iodine and Astatine.
Fluorine was represented by symbol F, chlorine by Cl, Bromine by Br, Iodine by I and Astatine by As.
These halogens are a deficit of one electron to attain inert gas configuration.
Thus, these halogens react with alkali or alkaline earth metals to form salts.
For example, chlorine reacts with sodium to form sodium chloride, similarly with sodium forms sodium chloride.

Note:
Halogens mostly exist as non-metals and fluorine with atomic number $9$ is the element with high electronegative value in the periodic table. Chlorine is the element with high electron affinity. The atomic radius increases along the group.