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Question: ionisation energy across period 3

Overall ionisation energy increases across period 3. One reason for this is that electrons are in the same energy level, so the shielding force is simular for each of these elements. How does this lead to an overall increase of I.E. across the period?

Reply 1

harlz_chalamet

Proton number increases as you go across period 3. So there is a stronger electrostatic attraction between the outer most electron and the nucleus. The more Protons = the higher the electrostatic attraction = more energy required to remove the outer electron and so GENERALLY a higher Ionisation Energy as you go across period 3

Because you know the electrons are in the same energy level, shielding does not affect the Ionisation Energy that much when you go across period 3, so the only factor that really only affects Ionisation Energy for period 3 is the number of protons (aka nuclear charge)