Why does sodium's chemical Na potassium K and gold Au?

Answer 1

The symbol Au for gold is derived from the Latin word aurum.

The symbol K for potassium is derived from the Neolatin word kalium.

The symbol Na for sodium is derived from the Neolatin word natrium.

For the long discussion about the names see the link below.

Answer 2

These symbols come from Latin or Greek names for the elements. For example, sodium comes from the Latin word "natrium," potassium from the English word "potash," and gold from the Latin word "aurum." This is part of the historical convention in chemistry to represent elements with unique symbols.