Electronic Configuration of Atoms – Part 2 New!

In earlier blogpost, we have discussed how electronic configurations are different from Basic Chemistry (such as GCE O-Levels) and Advance Level Chemistry (such as GCE A-Levels).

Today we are going to continue where we left off.

Electronic configuration refers to the arrangement of electrons in atoms and they follow certain rules:

1. Each orbital can hold a maximum of 2 electrons

2. Electrons always go into an empty orbital with the lowest energy first

3. In a sub-shell, electrons stays as far apart as possible – thus 2 electrons will go into 2 different orbitals of same energy level, rather than fitting together into 1 orbital

4. Electrons always have a spin, they either spin up ↑ or down ↓

This is where you learn something known as Box-Diagram.

Say for Sodium (Z=11), we will have the following Electronic Configuration based on the rules above.

We can simplified it to 1s²2s²2p⁶3s¹.

Useful way to remember the order of filling orbitals with electrons:

1s2s3s3p4s3d4p5s

Hope you find the above useful. Drop me a comment, i would love to hear from you.

Related Articles:

• Atomic Structure: Filling of Orbitals
• Atomic Structure: Strategy on Order of Filling Orbitals
• Atomic Structure: 3 Rules of Writing Electronic Configurations of Atoms
• Electronic Configurations of Atoms – Part 1 New!
• Atomic Structure: Number of Orbitals & Electrons in Quantum Shells