What are the sublevels in an energy level of n=3?

s, p, d

Explanation:

the number of sublevels for an energy level is as follows:

for n = 1 : s

for n = 2 : s, p.

for n = 3 : s, p, d.

for n = 4 or higher : s, p, d, f.

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.