Group 1 Elements (Alkali Metals)

A set of vocabulary flashcards based on the lecture notes for Group 1 Elements, covering physical properties, reactivity trends, and specific chemical reactions with water, chlorine, and oxygen.

Alkali metals

The name given to the Group 1 elements, which include lithium, sodium, potassium, rubidium, caesium, and francium.

Group 1 Outer Shell Electrons

All Group 1 elements have one electron in their outer shell, which gives them similar chemical properties.

Physical Properties of Alkali Metals

They are very reactive, soft metals that have a low density.

Trend: Relative Atomic Mass

As you go down Group 1, the elements have higher relative atomic masses.

Trend: Melting and Boiling Points

As you go down Group 1, the elements have lower melting and boiling points.

Trend: Reactivity

Reactivity increases as you go down Group 1 because the outer electron gets further away from the nucleus, decreasing attraction and making it easier to remove.

1+ ions

The type of ions Group 1 elements easily form because they do not need much energy to lose their one outer electron.

Group 1 Ionic Compounds

Generally white solids formed when Group 1 metals react with non-metals; they dissolve in water to form colourless solutions.

Metal Hydroxides

Compounds produced along with hydrogen gas when Group 1 metals react vigorously with water; they dissolve to produce alkaline solutions.

Reaction with Water Equation

$$2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g)$$

Potassium and Water Reaction

A reaction that releases enough energy to ignite the hydrogen produced due to the high reactivity of the metal.

Reaction with Chlorine

Group 1 metals react vigorously when heated in chlorine gas to form metal chloride salts, such as $2NaCl(s)$.

Tarnishing

The process where Group 1 metals react with oxygen in the air to form a dull, metal oxide layer.

Lithium + Oxygen Products

Lithium reacts to form lithium oxide ($Li_2O$).

Sodium + Oxygen Products

Sodium reacts to form a mixture of sodium oxide ($Na_2O$) and sodium peroxide ($Na_2O_2$).

Potassium + Oxygen Products

Potassium reacts to form a mixture of potassium peroxide ($K_2O_2$) and potassium superoxide ($KO_2$).

Lithium Flame Color

Crimson.

Sodium Flame Color

Yellow.

Potassium Flame Color

Lilac.