5-Ethyl-3,3,4-trimethylheptane has 3 secondary carbon. A primary carbon written as 1° is a carbon that has one carbon atom attached to it. A secondary carbon written as 2° is a carbon attached to two other carbons, while a tertiary carbon written as 3° is a carbon attached to three other carbons.
3 secondary carbons are found in 5-ethyl-3,3,4-trimethylheptane.
Explanation:
5-ethyl-3,3,4-trimethylheptane's structure can be seen in the attached picture, in this structure, each vertex represents one carbon atom.
<em>A secondary carbon</em> is a carbon that is bonded to only 2 other carbon atoms, each secondary carbon is highlighted in blue in the attached picture.