[ilchanp]

I got CH3-CH(CH3)-CH(Cl)-CH3

But my professor responded saying "At least one of the atoms in your response has an invalid valence. If you don't see an atom underlined in red, look for an atom that violates the octet rule, or try expanding your shortcut groups."

Any help?

[Hunter2]

I also dont know what he is talking about. But if you have an reaction of 2-Methylbutane with chlorine You would obtain 2-Methyl-2-Chlorine-butane as main product.

CH₃-C(Cl)(CH₃)-CH₂-CH₃