Answer
See explanation
Work Step by Step
1. Valence electron configuration for alkaline earth metals
Alkaline earth metals all have two electrons in their outermost s-orbital:
General configuration: ns²
Examples:
Beryllium: 1s² 2s²
Magnesium: [Ne] 3s²
Calcium: [Ar] 4s²
Strontium: [Kr] 5s²
Barium: [Xe] 6s²
2. Common properties of alkaline earth metals
- Reactive metals, but less reactive than alkali metals. Reactivity increases down the group.
- Harder and denser than alkali metals.
- Shiny, metallic luster when freshly cut, tarnish in air.
- Low melting and boiling points compared to transition metals.
- Form ionic compounds, typically with 2⁺ cations.
- Conduct electricity and heat.
3. How alkaline earth metals are prepared
Alkaline earth metals are too reactive to extract by simple reduction. Methods include:
- Electrolysis of molten salts (like CaCl₂ → Ca + Cl₂)
- Reduction of oxides with aluminum or other metals (thermite-like reactions)
4. Predicted formulas of compounds formed
Alkaline earth metals form compounds with a 2:1 ratio for monovalent elements and 1:1 with divalent elements.
