How many electrons on n1 in Ca?

Calcium (Ca) has an atomic number of 20, which means it has 20 electrons. The electron configuration of calcium is 1s² 2s² 2p⁶ 3s², indicating that the first energy level (n=1) contains 2 electrons, which are in the 1s orbital. Therefore, there are 2 electrons on n1 in calcium.