Which set of elements has similar bonding properties?

The vertical side of the periodic table.

Explanation: They have the same number of valence electrons and chemical properties. (I'm not saying it's right just trying to help:) )

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.