Sir,

Tertiary alkyl halides are mentioned not to answer Wurtz reaction. The intermediate tertiary alkyl free radicalhave good stability where as the then formed tertiary alkyl carbanion is inductively less stable. So can we attribute the second fact to be reason for non invlvement of tertiary alkyl halides in Wurtz reaction?

Yes, Tertiary alkyl free radical is very stable in nature but still it does not  support Wurtz Reaction due to the formation of 3⁰ Carboanion (Which is very unstable in nature due to the +I effect of side alkyl groups)

Another reason of Wurtz Reaction is not suitable for tertiary alkyl halides due to side reaction involving elimintaion reactions.As steric-hindrance i.e. the factor which arises due to the bulkiness of to reacting alkyl, or rather, tertiary alkyl groups.