Alkali Metals

The video discusses alkali metals, highlighting their single outer electron and high reactivity. It covers lithium's reaction with water, producing hydrogen and heat. Alkali metals are low-density, soft, and have low melting points. Reactivity increases down the group due to electron shielding. They exist naturally as compounds, not free elements.

What is a key reason alkali metals are stored under oil?

• They are very dense.

• They react with air and moisture.

• They are highly flammable.

• They are radioactive.

Which property is common among the lightest three alkali metals?

• They have high melting points.

• They float on water.

• They are very hard.

• They are magnetic.

What color is associated with sodium when it reacts?

• Lilac

• Green

• Blue

• Orange

Why does reactivity increase down the group of alkali metals?

• Atoms have a smaller nucleus.

• Atoms have a higher melting point.

• Atoms have more full electron shells.

• Atoms have fewer electrons.

In what form do alkali metals naturally occur?

• As free elements

• As gases

• As compounds with non-metals

• As liquids