# Are there no d-electrons in calcium?

For calcium, the electron configuration is $\mathrm{1s^2\:2s^2\:2p^6\:3s^2\:3p^6\:4s^2}$. Does it mean there's no electron in d sub-shell? Also, how would one write the electron configuration for a calcium ion?

• What you provided is the ground-state configuration for calcium. In theory every atom "has" d-electrons, just not in the ground state. When excited (which is usually VERY rare), electrons can bump up to higher energy levels like p,d,f,etc. – khaverim Mar 5 '16 at 3:47