Explain the properties and reactions of alkali metals, ionization energy, and the difference between strong and weak bases.

Here are the answers to your questions:

i) The general name for the group in which elements P, Q, and R belong is alkali metals.

ii) Ionization energy is the minimum amount of energy required to remove one electron from a gaseous atom in its ground state.

iii) Element P has the highest ionization energy because it has the smallest atomic radius (two electron shells). The outermost electron is closer to the nucleus and experiences a stronger electrostatic attraction, requiring more energy to remove.

iv) Element Q (Sodium) reacts vigorously with water in an exothermic reaction, releasing a significant amount of heat. This heat is sufficient to melt the low-melting-point metal. The hydrogen gas produced causes the molten metal to move rapidly on the water surface, creating a hissing sound.

v) The equation for the reaction between element Q (Sodium) and water is:

$$2\text{Na(s)} + 2\text{H}_2\text{O(l)} \rightarrow 2\text{NaOH(aq)} + \text{H}_2\text{(g)}$$

b) A strong base is a base that completely dissociates or ionizes in water to produce hydroxide ions. An example is sodium hydroxide ($\text{NaOH}$). A weak base is a base that only partially dissociates or ionizes in water. An example is ammonia ($\text{NH}_3$).

c) i) Neutralization is a chemical reaction between an acid and a base, which results in the formation of a salt and water.