The Noble Gases: The Kings of The Periodic Table

By Christine Yakich

The Noble Gases of The Periodic Table

Group: 8A


  • He, Ne, Ar, Kr, Xe, Rn
  • Very unreactive
  • Stable s2p6 octet
  • *He is considered a noble gas because it has 2 electrons in a full energy level!

  • Atomic Radius

  • Ionic Radius

  • Ionization Energy

  • Electronegativity

  • Reactivity


Atomic Radius

Atomic radius  decreases from left to right within a period because of effective nuclear charge . As you move from left to right in a period, you are still in the same energy level which means the electron is still the same distance from the nucleus.  As you go down a group, the atomic radius increases because you are adding energy levels that are farther away from the nucleus.

Smallest to Largest:

  1. Helium
  2. Neon
  3. Argon
  4. Krypton
  5. Xenon
  6. Radon

Ionic Radius

The Noble Gases do not have an ionic radius . This is because they don't form ions. Ions are charged particles, and atoms become charged particles when they gain or lose electrons. Atoms only gain or lose electrons in an attempt to establish an octet, or 8 valence electrons. Octets are particularly stable electron arrangements. Noble gases already have 8 valence electrons (except for helium) and are in very stable states. They have no need to gain or lose electrons, so they are "happy".


No ions = no ionic radii.


Ionization Energy

Ionization energy increases from left to right within a period. Noble Gases have a very stable electron configuration, therefore, they have the highest amount of ionization energy within their periods. It decreases down a family because electrons farther from the nucleus are easier to remove.

Largest to Smallest:

  1. Helium (highest ionization level in the periodic table)
  2. Neon
  3. Argon
  4. Krypton
  5. Xenon
  6. Radon

Electronegativity is the ability of an atom to gain an electron. Every atom strives to gain eight electrons, which is the number of atoms in the outermost energy level of an atom. Since the noble gases already have eight electrons in their outer shells, they dont wan't to attract any more. Since electronegativity measures the amount of attraction between an atom and an electron, noble gases do not have electronegativity.

Noble Gases are extremely unreactive. This is because non-metals gain electrons. Since the noble gases do not need to gain any electrons because of their "stable octet", they don't react often. The most reactive non-metal would be the one with the fewest electrons to gain, 7A, and the one with the smallest radius since the new electron would be tightly held by the protons in the nucleus (F is the most reactive non-metal).

The End