What is a covalent bond?
2 marks · NormalDescribe what happens to the electrons in the outer shells of two hydrogen atoms when they form a molecule of hydrogen, H.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Each hydrogen atom shares its single electron with the other, so both have two electrons in their outer shell. Both have the same electron configuration as helium.
Also accept: Both hydrogens share their electrons to achieve a full outer shell of 2 electrons each.
Common mistakes: Thinking electrons are transferred, not shared.; Not mentioning configuration of both atoms.
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States that electrons are shared between the two hydrogen atoms.
B2 · 1 mark · Each hydrogen ends up with two electrons in its outer shell (like helium).
Worked solution
Each hydrogen atom shares its one electron with the other hydrogen atom (B1).
As a result, both have two electrons in their outer shell, the same as helium (B2).