Why do the noble gases NOT form compounds readily?
a. They have empty outer energy levels.
b. They have no electrons.
c. They have seven electrons in the outer energy levels.
d. Their outer energy levels are completely filled with electrons.

The answer is: d.Their outer energy levels are completely filled with electrons.
Noble Gases are called noble gases because they are a octet. This means they have 8 electrons on their last energy level and 8 is the “magic number” in atoms it is the most electrons an atom can have on its last energy level. The Nobel Gases don’t want to pair with anything because they are stable while all the other groups are not. All the other group want to be a Noble Gas.

hcl + naoh → h2o + nacl

explanation:

hcl + naoh → h2o + nacl   is the reaction that is correctly balanced.

however, pcl3 + h2 → ph3 +3hcl, 2ca+ 3cl2 → cacl3, and c5h12 + 5o2 → 5co2 + 6h2o are not correctly balanced.