The hydrogen atom, H, has an electron configuration of 1s1...

Question

QUESTION:The hydrogen atom, H, has an electron configuration of 1s1. It has one unpaired electron in its only electron orbital, 1s. The helium atom, He, has an electron configuration of 1s2. It has one pair of electrons in its only electron orbital (or shell), 1s. Why is hydrogen more likely to form H2 than helium is to form He2?

 

Options: 

 

Helium atoms prefer to bond with different atoms (than He), whereas hydrogen readily bonds with itself.

Helium atoms have a filled outer orbital (the s-orbital). There is no place for electron sharing that would have to occur to form He2. The outer orbital of the hydrogen atom is half-filled, which is ideal for electron sharing.

Hydrogen is more likely to form H2 than helium is to form He2 because the hydrogen atom has fewer electron orbitals than the helium atom.

 

OR

The hydrogen atom is intolerant of accepting another electron to share in its orbital. It prefers to not interact with other hydrogen atoms.

Answer 1

The second option is correct: Helium atoms have a filled outer orbital (the s-orbital). There is no place for electron sharing that would have to occur to form He₂. The outer orbital of the hydrogen atom is half-filled, which is ideal for electron sharing.

 

This is also the reason why Helium is listed as a noble gas. Noble gasses have a full octet and do not need to form bonds. In the case of Helium, the electron configuration is 1s², meaning that the 1s orbital only needs 2 electrons to be stable (seeing as 1p does not exist).