Write down the complete electronic configuration of Calcium. State its Valency. A

To write down the complete electronic configuration of Calcium, we need to know its atomic number. The atomic number of Calcium is 20.

The electronic configuration of Calcium can be written as: 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2.

Now, to determine the valency of Calcium, we need to look at its outermost shell, which is the 4th shell (4s^2). The valency of an element is determined by the number of electrons it can gain, lose, or share to achieve a stable electron configuration.

In the case of Calcium, it has 2 electrons in its outermost shell, which means it can lose these 2 electrons to achieve a stable configuration. Therefore, the valency of Calcium is +2.