Select all that apply. elements listed in vertical columns of the periodic table: )have similar chemical properties )increase in number of protons in descending order )are metals )can combine with each other chemically

A) Have similar chemical properties

and also

B) increase in number of protons in descending order

I have gotten these answers checked, they are correct.

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.