Question

Write down electronic configuration of mn 25 and count total number of electrons with n + l is equals to 4

Answer 1

Electronic Configuration

Humans by nature tend to be systematic and that is achieved by proper arrangement. Humans have tried to arrange the elements too. Efforts were made by various chemists, and Mendeleev was one of them. He arranged the elements by atomic weight.
Electronic configuration is the arrangement of electrons in an atom in different shells and sub-shells. After the discovery of the shells and sub-shells, various physical and chemical properties of the elements were linked to the electronic configuration. As a result, attempts were made to arrange elements by their electronic configuration, so that their properties would obviously fall in a trend. Subsequently, the modern arrangement is evolved wherein elements are organized by atomic number. This is known as the modern periodic table.
The modern periodic table has elements arranged according to their electronic configurations. From left to right, i.e., in a period, the arrangement is such that each subsequent electron is added to the same shell. There are certain steps for writing the electronic configuration.
Step-1
Find out the atomic number of the element from periodic table. Since, in an atom, the number of protons which is the atomic number is equal to the number of electrons, the atomic number will give you the information about the number of electrons in that atom . Let's take the example of calcium. The atomic number of calcium is 20.
Step-2
Follow the electron configuration chart.
Electron Configuration Chart
Now, fill electrons by following the arrows of the electron configuration chart. Remember that the s-orbital can accommodate a maximum of two electrons while the p-orbital sets can hold six electrons in three orbitals. In the same way d-orbital set contains ten and f-orbital sets contain fourteen electrons in five and seven orbitals respectively.
Step-3
After filling given electrons in the energy levels, write the electronic configuration in the given manner.
[X] [Y] [Z]
Where, X represents the energy level, Y is for the sub-shell which is named as s, p, d and f. The number of sub-shells increases with the energy level. The number Z is the number of electrons present in a sub-shell.
We can represent electron configuration chart by using principle quantum number notifications also.
Quantum Number
For filling given electrons, we have to start form the K shell and move to higher levels.


Electronic Configuration in the Period
Example
Configuration of Li atomic number. 3, is 1s2 , 2s1
Configuration of Be atomic no. 4, is 1s2 , 2s2
Configuration of B atomic no. 5, is 1s2 , 2s2, 2p1
Configuration of C atomic no. 6, is 1s2 , 2s2 , 2p2
and so on till Neon,the last element.
This addition of each subsequent electron results in a completely new configuration and as a result the chemical properties of the subsequent element changes gradually. At the end of each row, a drastic shift occurs in the chemical properties.
Use the below widget to find the electron configuration.