Answer: Low electronegativity and large size of the metal (strong electropositive character).
- A Low electronegativity and large size of the metal (strong electropositive character)
- B An unusually high electronegativity of the metal element forming the hydride
- C A particularly small atomic size of the non-metal that hydrogen bonds to
- D Simply maintaining a high reaction temperature throughout the synthesis process
Correct answer: A. Low electronegativity and large size of the metal (strong electropositive character)
Explanation: Ionic hydrides form when electropositive metals (Li, Na, Ca) transfer electrons completely to H; covalent hydrides form when electronegativity difference is small.
Each water molecule's O-H bonds (covalent, solid) can hydrogen-bond (dashed) to neighbouring molecules, forming an extended network responsible for water's unusually high boiling point and density anomaly.
Concept context
The simplest and most abundant element in the universe. Study its unique position in the periodic table, isotopes (protium, deuterium, tritium), properties of water and hydrogen peroxide, and industrial uses.