Soda contains molecules that are forced into a mixture with water molecules because of the pressure. opening the can of soda will release the pressure, which allows the to escape from the mixture and form bubbles.

The soda bottle contains water and carbon dioxide as gas.

When we open a soda bottle we observe a fizz, this is opening of can of soda and releasing pressure. the carbon dioxide gas escaped out from the can.

This escaped carbon dioxide gas is the fizz or the bubbles observed during opening of soda can.

the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.