a, Ionisation is the energy required to remove an electrons from a neutral gaseous atoms and convert it into positively charged gaseous ion. The energy data shows the energy level of aluminium, 1S2 = 1n 2s2 2p6 =2n 3s2 3p1 =3nThe three electron in first section (3s2 3p1 =3n) these electrons are removed from the energy level furthest from the nucleus. Electrons in the outer energy level require less energy to remove due to the weaker electrostatic attraction from the nucleus.Electrons in the ( 2s2 2p6 =2n ),these electrons are removed from the second main energy level.the Jump between the 3rd and 4th ionisation energies is evidence of existence of energy level within the atom. Electrons in (1S2 = 1n ), these electrons are being removed from the energy level closest to the nucleus , electrons in the inner energy level require the most energy to remove because of the strong electrostatic attraction from the nucleus. For each successive Ionisation energy , the proton:electron ratio increases.
Therefore the is more positive charge attracting the remaining electrons each time. Electrons being removed( outermost) electrons attracted more strongly.From the 4th-10th , the larger increase in IE between the 9th and 10th values occurs because the 10th electron is removed from the 2s sub level which makes a stronger electrostatic attraction from the nucleus.