name the following branched alkanes:\n1.\n2.\n3.\n4.\n5.\n6.\n7.

Answer

For each structure, find the longest continuous chain of carbon atoms. This will be the parent alkane name.

Number the carbon atoms in the longest chain starting from the end closest to a substituent.

Name the alkyl groups attached to the main chain. Common alkyl groups are methyl ($-CH_3$), ethyl ($-CH_2CH_3$), etc.

Use the carbon - atom number to indicate where the substituents are attached to the main chain.

Arrange the substituents in alphabetical order and write the full name of the branched alkane.

The longest chain has 3 carbon atoms (propane), and there is a methyl group on the second carbon. The name is 2 - methylpropane.
The longest chain has 4 carbon atoms (butane), and there is a methyl group on the second carbon. The name is 2 - methylbutane.
The longest chain has 7 carbon atoms (heptane), and there is an ethyl group on the fourth carbon. The name is 4 - ethylheptane.
The longest chain has 7 carbon atoms (heptane). There is a methyl group on the fourth carbon and an ethyl group on the fifth carbon. In alphabetical order, the name is 4 - methyl - 5 - ethylheptane.
The longest chain has 8 carbon atoms (octane). There is a methyl group on the third carbon and a propyl group on the sixth carbon. In alphabetical order, the name is 3 - methyl - 6 - propyloctane.
The longest chain has 9 carbon atoms (nonane). There is a methyl group on the fifth carbon. The name is 5 - methylnonane.
The longest chain has 8 carbon atoms (octane). There is a methyl group on the second carbon and a butyl group on the sixth carbon. In alphabetical order, the name is 2 - methyl - 6 - butyloctane.