Question

Will `"2-pentylene"` generate geometric isomers?

Answer 1

Certainly, `"2-pentylene"` will generate geometric isomers....

Explanation:

And thus....the trans isomer....

And the cis isomer....

And these are GEOMETRIC isomers with distinct physical properties even given their identical `C-C` connectivity.

And for `"2-methylbut-2-ene"` we gots....

`(H_3C)_2C=CHCH_3`, which does not generate geometric isomers....

`"3-hexene"` will also generate a pair of geometric isomers. How?

`"2-ethylbut-1-ene"` is out of the running....

And `"3,3-dimethylbut-1-ene"` is likewise a non-starter,

`H_2C=CHC(CH_3)_2CH_3`

How do you know? Write the molecule out as a line drawing, and use molecular models if you are unsure.