Answer:
C. An electron has a high probability of being in certain regions.
Explanation:
In the electron cloud model, there are no electron-orbits around the nucleus but a cloud. This cloud has various densities with respect to distance from the nucleus. The most dense region of the cloud (which is the region close to the nucleus) is where electrons has the highest probability of existence.
The model explains that an electron a greater chance of being in the region closer to the nucleus. Thus, an electron has a high probability of being in certain region of the cloud about the central nucleus. And an electrostatic force exists between the nucleus and the electrons.
Answer: 
is the limiting reagent
Explanation:
To calculate the moles :
The balanced chemical reaction is :
According to stoichiometry :
1 moles of require = 2 moles of 
Thus 0.625 moles of will require=
of
Thus is the limiting reagent as it limits the formation of product and is the excess reagent as it is present more than the required amount.
1. c
2. a
3. a
(I’m not 100% but 2 & 3 couldn’t be transform)
