How does the valency of hydrogen differ from the valency of most other elements?
- A It can be positive or negative.
- B It is always positive.
- C It is always negative.
- D It has no valency.
The valency of hydrogen is unique compared to most other elements because it can be either positive or negative, depending on the type of atom or ion it is bonding with. In many compounds, hydrogen exhibits a positive valency, meaning it behaves as a positive ion (H+) or shares an electron with another atom. This is common in covalent compounds such as water (H2O) and hydrocarbons, as well as in many organic molecules. In these cases, hydrogen tends to lose its electron to the more electronegative atom it is bonded with. On the other hand, hydrogen can also exhibit a negative valency in certain compounds, such as metal hydrides (e.g., sodium hydride, NaH). In these cases, hydrogen acts as a hydride ion (H-), gaining an electron from the metal atom it is bonded with and forming an ionic compound. This versatility in valency makes hydrogen a unique and essential element in numerous chemical reactions and compounds.
