Question

What is the s, p, d, f configuration of Barium?

Answer 1

Hint :Remember the step wise energy levels of the orbitals. Fill the total number of electrons in the increasing energy level of orbitals as stated in the Aufbau principle. Then to simplify the electronic configuration use the noble gas configuration.

Complete Step By Step Answer:
We know that we fill electrons according to the Aufbau principle which states that we should fill the electron into orbitals in the increasing order of orbital energy level. The lowest energy orbitals are filled first.
The symbol used for writing the electronic configuration starts with the shell number(n) followed by the type of orbital and finally the superscript indicates how many electrons are there in the orbital.
Barium is found in the $6th$ energy level (row) of the periodic table. It is also found in the $2nd$ group of the periodic table. The first two groups (columns) of the periodic table represents the s orbital group. This means when we write the s, p, d and f electronic configuration of barium it will end with $6s^2$ because of the $6th$ row, s block and $2nd$ column.
The full electron (s, p, d, f) configuration would be:
 $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^{6}6s^2$
However we can simplify it by using noble gas notation or core notation by using the portion that represents noble gas electronic configuration. Here following represents the noble gas configuration of Xenon-
 $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}5s^{2}4d^{10}5p^6$
So the configuration of barium can be written as:
 $[Xe]6s^2$

Note :
Always fill the electrons in increasing energy of the orbitals first and then to simplify it using the Noble gas configuration. Learn the atomic number and position of the elements in the periodic table as they will help to write electronic configuration as well as to understand their characteristic properties.