Question 5

Two of most unique elements on the periodic table are hydrogen and helium. What makes them so unique and removed from the other groups on the periodic table?

a
Unlike all other elements, hydrogen and helium are gases
b
Unlike all other elements, hydrogen and helium are not considered metals
c
Unlike all other elements, hydrogen and helium only have a maximum of 2 valence electrons
d
Unlike all other elements, hydrogen and helium have very limited properties

1 answer

The correct answer is:

c. Unlike all other elements, hydrogen and helium only have a maximum of 2 valence electrons.

Hydrogen has one electron and can hold a maximum of two (when it forms a bond), while helium has two electrons and is considered a noble gas. This characteristic makes them unique compared to other elements on the periodic table, which typically have more valence electrons.