9. Elements in group 2 (IIA) are metals.
10.
- Elements in group 1 (IA) are classified as alkali metals and typically form +1 ions.
- Elements in group 6 (VIA) are classified as chalcogens and typically form -2 ions.
- Elements in group 7 (VII) are classified as halogens and typically form -1 ions.
- Elements in group 8 (VIII) are classified as noble gases and typically do not form ions.
11.
- Alkali Metals (Group 1) are very reactive because they have one valence electron which makes them highly likely to lose that electron to achieve a stable electron configuration.
- Alkaline Earth Metals (Group 2) are reactive but less so than alkali metals because they have two valence electrons.
- Halogens (Group 7) are very reactive because they have seven valence electrons and are only one electron away from completing their outermost shell.
- Noble Gases (Group 8) are very non-reactive because they have a full outer electron shell, making them stable and less likely to form bonds with other elements.
12.
A. Group A elements (Alkali Metals) would form ionic bonds with group D elements because alkali metals have a tendency to lose their outer electron(s) to achieve a stable electron configuration, while group D elements typically gain electrons.
B. Noble Gases (Group 8) have orbitals that are completely full, making them very stable and non-reactive. This is because they already have a full outer electron shell, so they have no need to gain or lose electrons to achieve stability, making them very unreactive.