Answer:
a and B are correct
Step-by-step explanation:
The energy of an electron associated with one shell around the nucleus is quantized. And is given by the formula
.
where n= shell number 1,2,3...
It is true that energy of an electron cab be measured and Each electron around an atom has a discrete measure of energy associated with it. Moreover, quantity of electron energy remains constant in a shell and changes only when the electron changes its shell.
hence C is incorrect.