Which of the following non-metals is lustrous? MCQ with Answer and Explanation

Explanation:
Magnesium oxide (MgO) is an ionic compound. Magnesium (2,8,2) loses two electrons to become Mg²⁺, and oxygen (2,6) gains two electrons to become O²⁻. This electron transfer forms an electrovalent (ionic) bond. Covalent bonds involve sharing (e.g., H₂O).

Explanation:
Reactivity series order: Na > Zn > Fe > Cu. Sodium (alkali metal) is extremely reactive, reacting violently with water. Copper is low in the series, hence used for water pipes.

Explanation:
Zinc (Zn) is a micronutrient required in small amounts for plant growth, enzyme activation, and chlorophyll synthesis. Nitrogen, phosphorus, potassium are macronutrients (primary). Micronutrients: Fe, Mn, Zn, Cu, B, Mo, Cl. Deficiency of Zn causes stunted growth and chlorosis. Fertilizers often include micronutrients.