Honest answers only

Chocolate.

Because good.

What do I win ?

Sodium. When I was a kid, it was easy to buy, and is a great starter for a ton projects, where you might need:

1. An instant, and intense hypothermic reaction.
2. Hydrogen
3. Corrosive liquid - Sodium hydroxide

Potassium.

Because it was only one I remember

How do you know if people are being honest?

Are we in science class? I forgot to study.

Alkali metal? That's a sub-genre I've never listened to before.

Shit. Confessedly, I'm clueless. My father taught Chemistry......I made a point to dodge his class....that bleddy periodic table was too extensive. I was good with NPK, only because I was spreading it on our farm fields.

Potassium because I like bananas

Sodium, because it can be combined with chloride to make my food taste better.