I choose the option A.
The electron absorbs energy from specific wavelength then moving from a lower energy orbital to a higher energy orbital.
A. How religion and philosophy different
All the other choices (b-d) can be explained by science while a can be explain by history I think
<span>when the number of moles Ca = mass of Ca / molar mass of Ca.
and we can get the molar mass of Ca, it is = 40 g/mol
and we have already the mass of Ca (given) = 9.8 g
so, by substitution: the moles Ca = 9.8 g / 40 g/mol
= 0.245 moles</span>
