Los metales alcalinos

The video tutorial explains the properties and reactivity of alkali metals, which include lithium, sodium, and potassium. These metals are highly reactive due to having one outer electron, and they react vigorously with water, releasing hydrogen gas and forming alkaline solutions. The reactivity increases down the group due to additional electron shells. Alkali metals are soft, have low densities, and low melting points. They do not occur freely in nature but are found in compounds like sodium chloride. The video also highlights the trends in reactivity and physical properties as you move down the group.

What is a key characteristic of alkali metals that makes them highly reactive?

• They are stored in water.

• They are non-reactive with air.

• They have one outer electron.

• They have a full outer electron shell.

Why should lithium be stored in oil?

• To prevent it from melting.

• To make it float in water.

• To enhance its reactivity.

• To prevent reaction with air and moisture.

What happens when sodium is dropped in water?

• It reacts quietly with no visible effect.

• It sinks and dissolves slowly.

• It forms a solid compound immediately.

• Orange sparks fly, similar to street lamps.

As you move down the group of alkali metals, what trend is observed in their reactivity?

• Reactivity increases.

• Reactivity remains the same.

• Reactivity fluctuates randomly.

• Reactivity decreases.

Why do alkali metals not appear in nature as loose elements?

• They are too dense to be found naturally.

• They are too soft to exist independently.

• They have high melting points.

• They are highly reactive and form compounds.