Why is Na used as the symbol for sodium?

The symbol "Na" for sodium comes from its Latin name, "natrium." The element sodium was first isolated and recognized as a distinct element in the early 19th century by Sir Humphry Davy. At that time, the Latin term "natrium" was commonly used to refer to sodium compounds like sodium carbonate.

When Davy discovered sodium, he chose to retain the traditional name "natrium" but anglicized it as "sodium." The symbol "Na" is derived from the first two letters of the Latin term "natrium," as was the convention for naming elements during that period. Similarly, other elements like potassium (K) and iron (Fe) also have symbols derived from their Latin names, kalium and ferrum, respectively.

It's worth noting that the choice of symbols for elements is often based on historical and linguistic factors, and while some symbols may seem unrelated to the English names of elements, they often have roots in their Latin or other language names.