The energy states that are available in each atom are represented by the energy level diagram.
Explanation of energy level diagrams hydrogen(or hydrogen-like atoms) and multielectron atoms:
Diagrams displaying the arrangement of subshells or orbitals in ascending energy level order are known as energy level diagrams.
A molecule or atom travels from a lower energy level to a higher energy state when it receives energy from light, colloids with another atom, or ions.
In most cases, the emission begins from an atom that's been excited to its higher state either through collision or through absorption of a nearby light.
In multi-electron atoms, their energies depend on both principal quantum number(n) and azimuthal quantum number(l).
Orbitals of hydrogen & hydrogen-like particles depend only on the value of the principal quantum number(n).
Important findings from energy level diagrams include:
The energies of a specific shell's subshells are not equal. Example: The energies of 2s and 2p are different.
In a specific shell, the energy of a subshell with a lower value of l is lower. 2s (l=0) has less energy than 2p (l=1) in the second shell.
The energies in the third shell are in this order: 3s, 3p, and 3d.
They are in the fourth shells in the following order: 4s, 4p, 4d, and 4f.
For the very same n value, the variations in energy between the s and p subshells are minor, whereas they are much larger between the p and d subshells, and so on.