Which of the following is true about the gas we call “air.” (the atmosphere)

a. composed mostly of the elements carbon and oxygen.

b. composed of molecules relatively far apart.

c. never contains water vapor.

d. all of the above

B. Composed of molecules relatively far apart.

Explanation:

The gas we call "air" has molecules that are relatively far apart.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

since electrons are negative the answer is neagtaive