Hello!
The atomic number is determined only by the number of protons in the nucleus of an atom. But, in a neutral atom it also represents the number of electrons in the electron cloud.
Neutrons are only important in the nucleus for helping us find atomic weight, which varies as we move along the perodic table and does not always equal the same amount of it's atomic number. Which is why it would not be a suitable answer for the first blank space. Electrons do not work either as they do not exist inside the nucleus but rather outside the atom.
The second space, since it states is in the electron cloud, we can deduct that electrons would be an appropriate answer there.
If you need anymore help feel free to ask, but I hope this answers your question.
I think it's Letter c.13 if I'm not mistaken
Answer: There are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.
Explanation:
Given: 
= 2.25 L, 
= 9.0 mol
= 1.85 L, 
= ?
Formula used to calculate the moles of helium are as follows.
Substitute the values into above formula as follows.
Thus, we can conclude that there are 7.4 moles of helium gas present in a 1.85 liter container at the same temperature and pressure.
Animalia and Plantae
Hope that helps
