Draw the electron configuration for a neutral atom of calcium

In order to write the Calcium electron configuration we first need to know the number of electrons for the Ca atom (there are 20 electrons). When we write the configuration we'll put all 20 electrons in orbitals around the nucleus of the Calcium atom.

In writing the electron configuration for Calcium the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Calcium go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s if now full we'll move to the 3p where we'll place the next six electrons. We now shift to the 4s orbital where we place the remaining two electrons. Therefore the Calcium electron configuration will be 1s22s22p63s23p64s2.

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.