Reasoning: Reactivity increases down Group I due to increased atomic size and decreased ionization energy, so potassium reacts more vigorously than sodium.

Reasoning: Softness increases down Group I because metallic bonding becomes weaker due to larger atomic size.

Reasoning: Group I elements lose one electron to form + 1 ions; this trend applies to all alkali metals.

Reasoning: Group I metals form +1 ions, so they combine with Cl⁻ in 1 :1 ratio.

Reasoning: Reactivity increases down Group I ; cesium reacts extremely violently with water.

Reasoning: Metallic bonding weakens down the group, lowering boiling points.

Reasoning: Reactivity increases down Group I, so potassium reacts faster with oxygen forming oxides / peroxides.

Reasoning: Alkali metals are highly reactive, especially heavier ones like rubidium.

Reasoning: Basicity of hydroxides increases down Group I.

Reasoning: Larger atoms have weaker attraction between nucleus and valence electron, lowering ionization energy.

Reasoning: Each alkali metal produces a characteristic flame; potassium gives a lilac / violet flame.

Reasoning: Heavier alkali metals tend to form peroxides and superoxides instead of simple oxides.

Reasoning: Density shows irregular trend due to structural differences, though generally increases from Li to Cs with anomalies.

Reasoning: Francium, being lowest in Group I, is predicted to be most reactive.

Reasoning: All Group I elements have one electron in their outermost shell, responsible for similar chemical behavior.

Reasoning: Reactivity increases down Group I, making rubidium highly reactive with water.

Reasoning: Larger atoms lose electrons more easily, increasing metallic character down the group.

Reasoning: All alkali metal salts are generally soluble in water.

Reasoning: Each step down Group I adds a new electron shell, increasing atomic radius.

Reasoning: High reactivity causes them to exist in combined forms, not in free state.