Question

What is the electron configuration of\[C{a^{ + 2}}\]?

Answer 1

Hint: We have to know that the atomic number of the atom is equal to the number of protons or the number of electrons. In every atom the number of protons and the number of electrons are equal. The electrons in the atom are filled by the lower energy level to the higher energy level. In modern periodic table elements are arranged in the table depending on the atomic number. In this way only periods and rows are arranged in the modern periodic table.

Complete answer:
The symbol of calcium is \[Ca\]. The atomic number of calcium is \[20\] and the total number of electrons is \[20\]. In this twenty electrons, first two electrons are going to filled in the first energy level \[1{s^2}\], next eight electron are going to filled in the second energy level \[2{s^2}\,2p_x^22p_y^22p_z^2\] and next eight electron are going to filled in the third energy level \[3{s^2}\,3p_x^23p_y^23p_z^2\] and remaining two electrons are going to filled in the fourth energy level \[4{s^2}\,\].
 The electronic configuration of the element calcium is \[1{s^2},\,2{s^2}\,2p_x^22p_y^12p_z^1,3{s^2}\,3p_x^23p_y^23p_z^2,4{s^2}\,\].
The electronic configuration of \[C{a^{ + 2}}\] is \[1{s^2},\,2{s^2}\,2p_x^22p_y^12p_z^1,3{s^2}\,3p_x^23p_y^23p_z^2.\]. Because it donates two electrons for stability.
According to Pauli principle, Aufbau principle and Hund’s rule, the electronic configuration of the \[C{a^{ + 2}}\] is \[1{s^2},\,2{s^2}\,2p_x^22p_y^12p_z^1,3{s^2}\,3p_x^23p_y^23p_z^2.\].

Note:
We need to remember that the number of electrons in the atom is equal to the atomic number of the atom. The electron fills in the atomic orbital of the atom. The electron fill in the atomic orbital is followed by the three important principles. There is the Pauli exclusion principle, the Aufbau principle and Hund’s rule. In the Aufbau principle, the electrons are filled in the orbital in the order of increasing the energy level of the orbital. First lower energy orbital filled followed by higher energy orbital are filled. In Pauli principle, no two electrons in the same orbital have the same quantum number. In Hund’s rule, the orbital must have multiplicity rather than pairing effect. Electrons are filled with each electron in one orbital in the same energy level then it goes to a pair of electrons in the orbital.