Helium is in group 18 of the periodic table. How is helium different from the other elements in this group?(1 point)

Question

Responses

Helium atoms have a full outer energy level, while atoms of the other elements in the group do not have a full outer energy level.
Helium atoms have a full outer energy level, while atoms of the other elements in the group do not have a full outer energy level.

Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.
Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.

Helium atoms have valence electrons in the first energy level, while atoms of the other elements in the group have valence electrons in the second energy level.
Helium atoms have valence electrons in the first energy level, while atoms of the other elements in the group have valence electrons in the second energy level.

Helium atoms have 2 electrons, while atoms of the other elements in the group all have 18 electrons.

Answer 1

The key difference between helium and the other elements in group 18 (the noble gases) is:

Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.

This is the correct statement, as helium is unique in that it has a complete outer shell with just 2 electrons, while other noble gases like neon, argon, and xenon have full outer shells with 8 electrons.