Question

as we know that there is force of repulsion between two same charge then how bonds are formed between two negatively charge electron.​

Answer 1

Answer:

Everything in the universe have natural tendency to attain stability. Therefore atoms want to pursue stability either by accepting, donating or sharing electrons. therefore to gain stability bond formation take place between negatively charged electrons.

Explanation:

Yes, its quite right electrons with posses negative charge and in obvious way they repel each other and bond formation is absolutely a difficult process.

But bond formation is not only dependent on type of charges but dependent on some other factors. Everything in the universe have natural tendency to attain stability. Therefore atoms want to persue stability either by accepting, donating or sharing electrons. Scientists introduced certain configurations which provide stability  

For example

Consider sodium containing one electron in the outermost shell and just missed the stability due to that one electron. In the meanwhile chlorine just needs one electron to attain argon like configuration. However, electrons now repel more in chlorine then repelling initially but now atom on the whole display stability. So, this repulsion on the whole display additional stability.

 Similarly, in sodium the repulsion increases which increases the nuclear pull but atom on the whole gain stability. So, electronic repulsion may cause unfavorable state but on the whole carry atom to the new hieght of stability.