Why does helium not fit the rule?

By bonding, there is a sharing between them of electrons, resulting in 8 in the valence shell of all the atoms, following the octet rule. Helium however, only has room for two electrons in its only valence shell and it is stable. Therefore, it doesn not follow the octet rule.

Why is helium 2nd on the periodic table?

The atomic number of helium is 2, meaning each atom of helium has two protons. The most abundant isotope of the element has 2 neutrons. This is because the most common isotope of hydrogen has one proton and no neutrons, while each helium atom typically has two neutrons as well as two protons.

Why helium is normally placed in Group 18 instead?

They have completed outermost shell. As helium has completed outermost shell it is placed in 18th group. Hence helium is placed in 18th group . It can only hold 2 electrons in its outer most shell.

Why is helium on the top of the periodic table?

Find Helium on the Periodic Table. Helium is the second element on the periodic table. This group contains the noble gases, which are the most chemically inert elements on the periodic table. Each He atom has two protons and usually two neutrons and two electrons.

Does helium follow the duet rule?

However, many atoms below atomic number 20 often form compounds that do not follow the octet rule. For example, with the duet rule of the first principal energy level, the noble gas helium, He, has two electrons in its outer level.

Is helium a Group 8 element?

Group 8A — The Noble or Inert Gases. Group 8A (or VIIIA) of the periodic table are the noble gases or inert gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

Why does helium only have two valence electrons?

Explanation: Helium is located in period 1, group 18 of the Periodic Table and has an atomic number equal to 2. As a result, neutral helium will only have 2 electrons surrounding its nucleus. Two electrons in its outermost (and only) shell, two valence electrons.