An electron in the third shell has more energy than an electron in the second shell and An electron in the first shell has more energy than an electron in the second shell.
Explanation:
Calcium has 20 electrons.
Calcium does not "borrow" electrons. Calcium "donates" 2 electrons.
Calcium ion (Ca2+) has 18 electron
Calcium has 2 valence electrons.
The element Ca, so calcium, has 20 electrons (so it also has 20 protons) this means that it has 2 electrons in its outer orbit, its relative atomic mass is 40.
