Question

What are the following groups known as?
(1) Group $1$
(2) Name two elements of the group

Answer 1

Hint : The periodic table is known as the tabular arrangement of all the chemical elements on the basis of their atomic numbers. The periodic table consists of groups and periods. The vertical columns are called ‘groups’ and the horizontal rows are called ‘periods’.

Complete Step By Step Answer:
Group $1$ is also known as alkali metals.
Sodium and potassium are the two elements of group $1$ .
The compounds are known as alkali metals because when they react with water, they usually form alkalis which are strong bases that can easily neutralize acids. Alkali metals occupy the first column of the periodic table. Alkali elements are Lithium ( $Li$ ), Sodium( $Na$ ), Potassium ( $K$ ), Rubidium ( $Rb$ ), Caesium ( $Cs$ ) and Francium ( $Fr$ ) occupying successive periods from first to seven.
Alkali metals are known to have one electron in their valence shell. They tend to lose the outer shell electron to form cations with charge $+ 1$ .This property makes them the most electropositive elements and due to the same reason, they are not found in the pure state.
As alkali metals are very soft, alkali metals have low melting and boiling points compared to the other period elements. Melting and boiling points decrease from Lithium to Caesium.

Note :
Hydrogen is placed above group $1$ . Hydrogen ( $H$ )is not considered as an alkali metal as it is mostly found as a gas when the temperature and pressure are normal. Hydrogen can show properties of an alkali metal when it is exposed to extremely high pressure.