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.

How do the physical properties of alkali metals change as you move down the group?

Why do alkali metals exist naturally as compounds rather than free elements?