S-Block Elements: A Chemistry Overview
S-Block elements are the first two groups in the periodic table: Group 1 (alkali metals) and Group 2 (alkaline earth metals). These elements are characterized by having their outermost electron in the s orbital.
Alkali Metals (Group 1)
Members: Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).Properties:
- Highly reactive metals
- Low melting and boiling points
- Soft and malleable
- Form ionic compounds with non-metals
- React vigorously with water to produce hydrogen gas and a metal hydroxide
- Examples of compounds: Sodium chloride (NaCl), Potassium hydroxide (KOH)
Alkaline Earth Metals (Group 2)
Members: Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).Properties:
- Less reactive than alkali metals
- Higher melting and boiling points
- Harder and denser than alkali metals
- Form ionic compounds with non-metals
- React with water to produce hydrogen gas and a metal hydroxide, but less vigorously than alkali metals
- Examples of compounds: Calcium carbonate (CaCO₃), Magnesium oxide (MgO)
General Properties of S-Block Elements
- Electron configuration: ns¹ (for alkali metals) and ns² (for alkaline earth metals), where n is the principal quantum number.
- Oxidation states: Alkali metals typically exhibit a +1 oxidation state, while alkaline earth metals exhibit a +2 oxidation state.
- Ionic character: S-block elements generally form ionic compounds with non-metals.
- Reactivity: Alkali metals are the most reactive metals in the periodic table, while alkaline earth metals are less reactive.
Key points to remember:
- The s-block elements are the first two groups in the periodic table.
- Alkali metals are highly reactive, while alkaline earth metals are less reactive.
- Both groups form ionic compounds with non-metals.
- The oxidation states of alkali metals are +1, and those of alkaline earth metals are +2.
