Electrostatic force:

Electrostatic forces of attraction and repulsion

The key to understanding the ionisation energy required to remove the first electron (1st ionisation energy) is a consideration of the forces holding the electron to the atomic nucleus. This is called electrostatic attraction.

The attractive force experienced by particles with opposite electrical charges (e.g. a proton and an electron. The repelling force experienced by two similar charges (e.g. two electrons)

The magnitude (size) of an electrostatic force is a function of the magnitude of each individual charge and the distance separating them.

Electrostatic force	Z+ Z-
	r2

Hence, the greater the charge on the nucleus the greater the attractive force.

The greater the distance between the electron and the nucleus the lower the attractive force.

The overall force felt by an electron is a balance of the attractive force felt from the positive nucleus and the distance from that nucleus.

There will also be a small repulsive force felt due to the other electrons between the nucleus and the electron in question (note that the majority of the electrons are not in the space between the nucleus and the electron in question and so they do not all exert a repulsive effect pushing the electron away from the nucleus)

Electrostatic force
The concept of electrostatic force underlies many areas of chemistry. Chemical reactivity is fundamentally caused by electrons and the forces that they experience. If an element easily loses its outer electron(s) then it's reactive. If you understand this concept you can apply it to explain many areas of chemistry.

close window