How does ionization energy change on the periodic table?

Ionization energy increases across a period and decreases down a group.

First: what is ionization energy ? It’s the minimum amount of energy required to remove an electron (to infinity) from the atom or molecule in the gaseous state

These are the factors that affect ionization energy:

  1. Atomic radius
  2. Nuclear charge
  3. Orbital penetration
  4. Electron pairing within a sub-shell
  5. Shielding or screening effect of the inner orbitals

Atomic radius:

  • When an atomic radius decreases, ionization energy increases.
  • Across a period, atomic radius decreases. Down a group, atomic radius increases. Therefore, across a period ionization energy increases down a group it decreases.

Nuclear charge:

  • If a nucleus has a positive charge, there is a stronger attraction for the electrons. This results in a high amount of ionization energy.
  • Across a period, attraction of electrons from the nucleus increases, while down a group it decreases. Therefore, across a period ionization energy increases down a group it decreases.

Orbital penetration:

  • Since the s orbitals penetrate towards the nucleus more closely than the p orbitals, it’s easier to remove electrons from p orbitals than from s orbitals.
  • Therefore, across a period ionization energy increases down a group it decreases.

Electron pairing within a sub-shell:

  • Since repulsion between electrons in the same orbital is higher than repulsion between electrons in different orbitals, within a sub-shell, paired electrons are easier to remove than unpaired ones.
  • Across a period ionization energy increases, down a group it decreases.

Shielding or screening effect of the inner orbitals:

  • Electrons in the outermost orbitals feel lesser attraction from the nucleus than expected, due to presence of electrons in inner orbitals.
  • Therefore, across a period ionization energy increases, down a group it decreases.

Overall: across a period ionization energy increases and down a group ionization energy decreases.

Show more







Calculate Your Essay Price
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more

Order your essay today and save 10% with the coupon code: best10