The first row is alkali metals. They’re so reactive you don’t find large maouns in ature. They need to be stored out of contact with air to prevent oxidation. The alkali metals are Lithium, Sodium, potassium, rubidium, caesium and francium. Francium is radioactive and very rare in nature. usually chemists extract these things from compounds containing them. Lithium, sodium and potassium may be familiar to you in chemical reactions.
These metals readily react with water and oxygen which is why they’re sometimes stored in oil in an airtight container, or an inert gas such as argon. Lithium normally floats in the oil. The heavier alkali metals react more vigirously than the light ones.
Pure sodium is softer than lithium, and easier to cut. Potassium is softer than sodium and easier to cut again. It reacts with water more vigrously than sodium.
They are called alkali metals because they react with water to form an alkaline solution.
When removed from oils and cut they are normally shiny and soft.
It has seven periods from top to bottom with an addition two rows
Lithium burns with a strong red flame. It reacts weith oxygen i nthe air to produce lithium oxide. It is the only one of the group to also react with the Nitrogen in the group to give Lithium nitride.
Sodium brbns with an orange glow. It produces a solid mixture of sdoium oxide, and sodium peroxide.
Potassium tends to melt in the air and turn into ptoassium peroxide, and potasisum superoxide. Potassium bruns with a lilac flame.
When put in water alkali metals tend to float. As you go down fro mtop to bottom the melting and boiling points decrease. As you go down top to bottom reactivy and density increases.