Question

helium is in group 18 of the periodic table. how is helium different from the other elements in this group? (1 point) helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons. helium atoms have 2 electrons, while atoms of the other elements in the group all have 18 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 a full outer energy level, while atoms of the other elements in the group do not have a full outer energy level.

Explanation:

Helium has an atomic number of 2 and its 2 electrons are in the first energy - level which is full with 2 electrons. Other group 18 elements have 8 valence electrons in their outer energy - level (higher than the first energy - level).

Answer:

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