In which atmospheric layers does temperature decrease with altitude? I. Troposphere
II. Stratosphere
III. Mesosphere
IV. Thermosphere
V. Exosphere

A. I and II
B. Only V
C. II and IV
D. I, III, and V

A- I and II

Temperature decreases as you gain altitude in the troposphere and mesosphere

a electronegativity decreases beacuse the size of nucleus is bigger.

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.