Question

Covalent bond formation

Answer 1

Given atoms X and Y, there are 4 types of electrostatic forces present between atoms as they approach each other.

1) Attraction force between valence electron X and nuclei Y

2) Attraction force between valence electron Y and nuclei X

3) Repulsion force between nuclei X and Y

4) repulsion force between Valence electron in X and Y.

Do the attraction forces dominate the repulsive forces as atoms approach other so that moving the opposite charges closer together 'll result into positive work and thus decrease in potential energy. Up to which point do we consider this is as happening.

Answer 2

here's a diagram to represent that https://www.google.com.au/search?q=covalent+force&espv=2&rlz=1C1OPRB_enAU585AU585&biw=1511&bih=714&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi2gajW-MLOAhVEVxQKHS4aAt8Q_AUIBigB&dpr=0.9#imgrc=Q7AjubdYhHBSIM%3A

Answer 3

You can also aid your self a little bit by remembering how we define a force:
\[\large F_x=\frac{ \partial E }{ \partial x }\]
This means that the slope tells you about the force from the energy diagram:
Negative force: Repulsion
Postive force: Attraction.
In the stationary point it should then be obvious that:
\[\Large F_x=\frac{ \partial E }{ \partial x}=0\]