What happens to the number of outermost electrons as you move across a period? a. as you move across a period, the number of outermost electrons decreases. b. as you move across a period, the number of outermost electrons becomes more positive. c. as you move across a period, the number of outermost electrons increases. d. as you move across a period, the number of outermost electrons remains the same.

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.