Ionization Energies Trend

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karinaseth_1A
Posts: 57
Joined: Sat Jul 20, 2019 12:15 am

Ionization Energies Trend

Postby karinaseth_1A » Mon Oct 21, 2019 10:07 pm

In lecture, we learned that ionization energies increase across a period because the effective nuclear charge increases. I understand this, but since more electrons are added across a period, shouldn't the shielding effect from those electrons also increase? And wouldn't this prevent the ionization energies from increasing across a period?

Justin Vayakone 1C
Posts: 96
Joined: Sat Sep 07, 2019 12:19 am

Re: Ionization Energies Trend

Postby Justin Vayakone 1C » Mon Oct 21, 2019 10:20 pm

I guess the increase in nuclear charge trumps the electron shielding. Maybe because when increasing across a period, the electrons added are valence electrons, so I think the electron shielding really isn't increasing much.

SarahSteffen_LEC4
Posts: 67
Joined: Sat Aug 24, 2019 12:17 am

Re: Ionization Energies Trend

Postby SarahSteffen_LEC4 » Mon Oct 21, 2019 10:22 pm

As you move from left to right across a period the nuclear charge of an atom increases, which trumps the shielding effect. Thus, ionization energy tends to increase across a period due to this increase in charge across a period.

Chantel_2I
Posts: 95
Joined: Sat Sep 07, 2019 12:19 am

Re: Ionization Energies Trend

Postby Chantel_2I » Tue Oct 22, 2019 6:12 pm

Moving from left to right, the electrons added are in the same energy level. Therefore, the effect of shielding does not increase drastically with the addition of each one in a single period.

sarahsalama2E
Posts: 148
Joined: Fri Aug 30, 2019 12:16 am

Re: Ionization Energies Trend

Postby sarahsalama2E » Tue Oct 22, 2019 6:18 pm

ionization energy is the energy required to remove an electron from an atom in the gas phase. The further away an electron is from the nucleus the easier it is to remove. Ionization energy increases across a period because the nuclear charge is greater and the electrons are still being added to the SAME shell so the effective charge is getting bigger. This is why the shielding effect does not also increase. For me, I think of the shielding effect as coming into play when we are adding shells AKA moving down a group--> this is why ionization energy decreases as we move down a group, because the attraction the outermost e- feel to the nucleus is not as strong because of shielding happening. Sorry if that was confusing, hope it helps.

Tiffany_Chen 2K
Posts: 96
Joined: Fri Aug 30, 2019 12:15 am

Re: Ionization Energies Trend

Postby Tiffany_Chen 2K » Tue Oct 22, 2019 7:15 pm

Ionization energy is the energy required to remove an electron from an atom in gas phase. Going across a period, you are increasing the number of photos while the number of shielding electrons (inner electrons) stay constant. So there will be an increase of effective nuclear charge, a tighter hold on the outer electrons and thus higher IE.


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