The electron configuration can also be represented by writing the symbol for the occupied subshell and adding a superscript to indicate the number of electrons in that subshell. For example, consider a carbon atom having an atomic number of 6. The total number of electrons in a neutral carbon atom is 6. The electron configuration of the carbon atom represented by the orbital diagram is This electron configuration can be written as 1s22s22p2 Use the rules for determining electron configurations to write the electron configuration for P . Express your answer in complete form in order of increasing orbital energy. For example, 1s22s2 should be entered as 1s^22s^2.

As stated, writing the symbol for the occupied subshell and adding a superscript to indicate the number of electrons in that subshell is a common way to represent the electron configuration of the atoms.

There are several rules that you have to follow to write such electron configurations. I will explain the needed to write the electron configuration for the atoms of P (phosphorus) in the requested form.

1) First, determine the number of electrons of the atom:

Use the atomic number. Phosphorus has atomic number 15.
The atomic number is the number of protons. So, phosphorus has 15 protons.
A neutral atom has the same number of electrons than protons. So, phosphorus atoms have 15 electrons.

2) Fill the orbitals in order of incrasing orbital energy

Aufbau rules are very helpful. As per it this is the order of the orbitals:

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ ...

15 electrons ⇒ 1s² 2s² 2p⁶ 3s² 3p³
Check the number of electrons: 2 + 2 + 6 + 2 + 3 = 15
Hence, that is the electron configuration for P iin complete form in order of increasing orbital energy.

3) Other rules that you must consult to deal with some special issues of the electron configurations are: the exclusion principle of Pauli and the Hund's rule, but they are beyond the interest of this question.