Question

Write the electronic configuration of chlorine atoms.

Answer 1

Hint: The atomic number of chlorine is 17. It is a group 17 element and belongs to the halogen family. Chlorine tends to attain its nearest noble gas configuration by attaining one electron. It is the second lightest halogen atom.

Complete step by step answer:
Chlorine is a chemical element of group 17 and belongs to the halogen family. It is represented by the symbol Cl and its atomic number is 17. It appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. It is a yellow – green gas at room temperature. It is an extremely reactive element and a strong oxidising agent. In the modern periodic table, it has the highest electron affinity and the third highest electronegativity on the Pauling scale. The most electronegative atom on the Pauling scale is fluorine, followed by oxygen and chlorine. The most common compound of chlorine is sodium chlorine (NaCl) which is also known as common salt.
Now, since the atomic number of chlorine is 17, it has 17 electrons and 17 protons as it is a neutral atom. The electrons are filled in the orbitals according to the Aufbau rule. Aufbau rule gives the order for the energy of orbitals. Hence, the electronic configuration of chlorine atom is: \[1{s^2}2{s^2}2{p^6}3{s^2}3{p^5}\]

Hence, the correct answer is \[1{s^2}2{s^2}2{p^6}3{s^2}3{p^5}\]

Note: Remember that according to the Aufbau rule, the energy of a 4s orbital is less than the energy of a 3d orbital. So, electrons in 4s orbital enter first.