Helium,He,is a nonmetallic gas and the second element in the periodic table.Rather than being placed adjacent to hydrogen,H,however,helium is placed on the far right of the table because
A)hydrogen and helium repel one another.
B)the sizes of their atoms are vastly different.
C)they come from different sources.
D)helium is most similar to other group 18 elements.

Question

Quizplus · Accepted Answer

Helium is placed on the far right of the periodic table because it shares properties with the noble gases in Group 18, such as having a full outer electron shell, which makes it very stable and unreactive.

Helium,He,is a Nonmetallic Gas and the Second Element in the Periodic