Ionisation Energies Explained
Ionisation energies? What are they?
The energy needed to form positive ions is known as ionisation energy (literally Ion- energy - simple right!). Ionisation energies provide evidence for a model of the atom in which electrons are arranged into shells. The first ionisation is a measure of how easily an atom looses an electron to form a 1+ ion.
"Enthalpy change when one mole of electrons is removed from one mole of gaseous atoms to from one mole of gaseous, uni-positive ions."
Factors of ionisation ~
Negative electrons are held in their shells by their attraction to the positive nucleus at the centre of an atom (as well you know...). In order to loose one of these electrons the force pulling the electron has to be stronger than the force holding it in pace. The electrons that are furthest away from the nucleus are lost first because the bond between them and the nucleus is the weakest. This is due to several factors which affect nuclear attraction...
1) Atomic Radius, The bigger the size of the atom (Atomic Radius) the further away the electron is going to be, therefore the weaker the bond. Elementary dear Watson... (sorry awful science joke!).
2) Nuclear Charge, The greater the nuclear charge (how many positive protons there are in the nucleus) the greater the attractive forces acting…