Question

Match the following groups with their descriptions (1 point)
Halogens
Alkali Earth Metals
Alkali Metals
Noble Gases
:: Group number 7, very reactive
:: Inert. Do not react with anything
:: Group number 1, very reactive
: Reactive, but not the most reactive
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?
(1 point)
• Unlike all other elements, hydrogen and helium have very limited properties
Unlike all other elements, hydrogen and helium only have a maximum of 2 valence electrons
• Unlike all other elements, hydrogen and helium are not considered metals
• Unlike all other elements, hydrogen and helium are gases

Answer 1

Matches
- Halogens — Group number 7 (7A), very reactive
- Alkali Earth Metals (alkaline earth metals) — Reactive, but not the most reactive
- Alkali Metals — Group number 1, very reactive
- Noble Gases — Inert. Do not react with anything

Second question — correct choice
- Unlike all other elements, hydrogen and helium only have a maximum of 2 valence electrons.

Brief explanation: H and He are in the first energy level (n=1), so their valence shell can hold at most 2 electrons, which makes them distinct from all other elements.