Are These Condensed Structural Formulas for C7H16 Correct?

[aatari]

Hi Guys, I attempted the question below and just need someone to have a look to make sure there are no mistakes.

1. Homework Statement
Write condensed structural formulas and the names for three constitutional (i.e. structural) isomers with the molecular formula C7H16.

Homework Equations

None.

The Attempt at a Solution

CH3CH(CH3)(CH2)3CH3 - 2-methylhexane

CH3CH2CH(CH3)(CH2)2CH3 - 3-methylhexane

CH3CH(CH2)(CH3)CH2CH3 - 3-ethylpentane

 

[Borek]

Last one is wrong, you have two separate substitutents on the second carbon, not an ethyl.

 

[aatari]

CH3CH(CH2)(CH3)CH2CH3 - 3-ethylpentane

So it should be CH3CH(CH2CH3)CH2CH3?

 

[mjc123]

That is 2-ethylbutane (AKA 3-methylpentane, naming it by the longest chain).

 

[epenguin]

So it should be CH3CH(CH2CH3)CH2CH3?

Isn't that C₇H₁₅ ?

And isn't there a very simple C₇H₁₆?