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Ionization Energy

Posted: Wed Oct 23, 2019 9:13 am
by SarahSteffen_LEC4
I understand why Ionization Energy decreases down a group, but why does it increase across a period?

Re: Ionization Energy  [ENDORSED]

Posted: Wed Oct 23, 2019 9:28 am
by Ryan Narisma 4G
Hi SarahSteffen_LEC4! The Ionization Energy typically increases as you move across a period (from left to right) due to the increase in the effective nuclear charge of the atom (basically the number of protons). Keep in mind that whenever you're adding an electron across a period, the electron remains in the same principle quantum energy level (otherwise known as n value in the quantum numbers). Because the nucleus of the atom gains a proton, the "pull" on the electrons in the outer energy level increases (because the electrostatic attraction between protons and electrons increases); therefore, the ionization energy (energy to remove an electron in an element in the gas state) increases because the nucleus is pulling onto those electrons and the nucleus won't let them go so easily. I hope this helps!

Re: Ionization Energy

Posted: Thu Oct 24, 2019 9:27 am
by Caroline Zepecki
As you move down the period, it would decrease because the repulsion amongst the electron cloud decreases, which lowers the ionization energy.

Re: Ionization Energy

Posted: Thu Oct 24, 2019 9:44 am
by Veronica_Lubera_2A
One helpful tip that helps me remember Ionization Energy increasing along the period is that F (Fluorine) is considered to be the strongest element its ability to remove electrons. So if you just keep in mind that Fluorine is the best, then you can think of the trends more easily.