Group 1 (Alkali Metals) (Edexcel IGCSE Science (Double Award): Chemistry): Flashcards

The alkali metals are the Group 1 elements: lithium, sodium, potassium, rubidium, caesium and francium. They are soft, low-density metals that form alkaline solutions when they react with water.

All Group 1 elements share similar chemical properties because they each have one electron in their outermost shell. This means they all need to lose just one electron to become highly stable.

True.

As you descend Group 1, each element has more electron shells, so the outer electron is further from the nucleus and more easily lost. This makes each successive element more reactive.

When a Group 1 metal reacts with water, a metal hydroxide and hydrogen gas are produced.

Alkali metals tarnish because they react with oxygen in the air to form a metal oxide, which appears as a dull coating on the surface. The rate of tarnishing increases going down the group.

False.

The melting point decreases going down Group 1. This is because the attractive forces between the outer electrons and the positive ions become weaker as the atoms get larger.

Potassium reacts with water more vigorously than sodium, and burns with a lilac flame.

All Group 1 metals react with water to produce a metal hydroxide and hydrogen gas, following the same general pattern: 2M (s) + 2H₂O (l) → 2MOH (aq) + H₂ (g). This consistent pattern of behaviour confirms they belong to the same chemical family.

1. Rubidium would react more vigorously with water than potassium, producing rubidium hydroxide and hydrogen gas

2. It would tarnish more rapidly in air, forming rubidium oxide