Write the formula and name of alkyl groups.

(N/A) In branched chain hydrocarbons,the alkyl group is present as a branch.
$\rightarrow$ Alkyl groups $(-R)$: The removal of one hydrogen atom from the molecule of an alkane gives an alkyl group.
$R-H \xrightarrow{-H} R-$
$\Rightarrow$ Nomenclature: $(\text{Alkane} - \text{ane} + \text{yl} = \text{Alkyl})$. These small alkyl groups are found in branched chain hydrocarbons. In a branched chain compound,small chains of carbon atoms are attached at one or more carbon atoms of the parent chain. The small carbon chains (branches) are called alkyl groups.
For example:
In a four-carbon containing parent chain,the $-CH_3$ (Methyl) alkyl group is in the branch.
In a five-carbon containing parent chain,the $-CH_3$ and $-CH_2CH_3$ groups are in the branch.
$(B)$ Nomenclature of alkyl group: In order to name such compounds,the name of the alkyl groups is prefixed to the name of the parent alkane.
$\rightarrow$ General formula of alkyl group: $C_nH_{2n+1}$
- Name of alkyl group: $(\text{Alkane} - \text{ane} + \text{yl}) = \text{Alkyl}$. One $H$ atom is less in an alkyl group than in the corresponding alkane.

Alkane (Formula,Name)	Alkyl (Formula,Name,Short Name)
$CH_4$,Methane	$CH_3-$,Methyl,$Me$
$C_2H_6$,Ethane	$CH_3CH_2-$,Ethyl,$Et$
$C_3H_8$,Propane	$C_3H_7-$,Propyl,$Pr$
$C_4H_{10}$,Butane	$C_4H_9-$,Butyl,$Bu$
$C_5H_{12}$,Pentane	$C_5H_{11}-$,Pentyl,$Pent$
$C_{10}H_{22}$,Decane	$C_{10}H_{21}-$,Decyl,$Dec$