When a chemical bond is formed, the constituent atoms acquire the valence electron configuration of noble gases called ?

These atoms are bonding to increase their stability and decrease their energy levels by bonding into electron configurations that follow the Octet Rule. The Octet Rule relates to atoms wanting to have 8 valence electrons in their outer-most electron shell. Noble gases are the only elements to already have 8 valence electrons before bonding. For this reason, Noble gases are usually already stable low energy atoms that are less likely to form bonds than all the other elements on the periodic table.

This is called fulfilling the Octet Rule.

Any Questions?

They are all decomposition reactions.

The air is going to come out because of the low pressure.