Element Formulas

Obj. 5. From the name of an element, determine the formula (if different from the symbol).

The only elements for which we have to deal with the formula being different from the symbol are the diatomic elements. The diatomic elements are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine and iodine. Remember, these nonmetals are found across the top of the periodic table, plus the halogens. (You could also remember S₈ and P₄ and other elements in their families, but the formulas of their molecules can change with conditions, and they are usually represented by their symbols rather than their formulas.) With that information, try your hand at exercise 5.

Exercises

Give the formula for each of the following elements if it is different than the symbol for the element.

a. hydrogen
b. sodium
c. silicon
d. nitrogen
e. oxygen
f. fluorine
g. neon

Answers to Exercises

Give the formula for each of the following elements if it is different than the symbol for the element.

a. hydrogen - The formula is H₂.
b. sodium - Sodium does not have a different formula, so we just use the symbol Na.
c. silicon - For silicon, we use the symbol Si.
d. nitrogen - Nitrogen has the formula N₂.
e. oxygen - Oxygen has the formula O₂.
f. fluorine - Fluorine has the formula F₂.
g. neon - For neon we use the symbol Ne.