Question

what is a unique characteristic of group 18 (noble gases)? 1 point they have 7 valence electrons they are highly reactive they have a full outer shell of electrons they are all metals what characteristic do alkaline earth metals share? 1 point they have 1 valence electron they are gases at room temperature they are white or silvery and malleable they are non-reactive

Explanation:

First Question (Characteristic of Group 18 - Noble Gases)

Noble Gases (Group 18) have a full outer electron shell (except Helium which has 2, others have 8), making them stable and non - reactive. Option A: They are not all metals (they are gases). Option B: Having 7 valence electrons is for Group 17. Option C: They are non - reactive, not highly reactive. So the correct option is the one with "They have a full outer shell of electrons".

Alkaline Earth Metals are in Group 2, have 2 valence electrons. They are metals, white or silvery, malleable, and solids at room temperature (not gases). Option A: Having 1 valence electron is for Group 1 (Alkali Metals). Option B: They are solids at room temperature. Option D: They are reactive (not non - reactive). So the correct option is "They are white or silvery and malleable" (the third option among the four for the Alkaline Earth Metals question).

Answer:

The option with "They have a full outer shell of electrons" (the second option among the four for the Group 18 question)

Second Question (Characteristic of Alkaline Earth Metals)