Figure 1-6. Writing the chemical formula of water (source).
Atoms of the same type (of the same element) can also bond together to form molecules. For example, a molecule of hydrogen consists of two hydrogen atoms, H-H, or H2
. Similarly, a molecule of oxygen, O2
, is produced from two oxygen atoms.
How are chemical formulas read and pronounced? That is easy. Just read the formula letter by letter and number by number. For instance, H2
is pronounced H-two. The formula of sulfuric acid, H2
, is pronounced H-two-S-O-four. For the formula of baking soda NaHCO3
, the pronunciation is N-A-H-C-O-three. 1.2.4. Exercises.
1. Find the following elements in the periodic table: H, C, N, O, Na, P, S, Cl, K, Ca, Cu, Si. What are the names and numbers of these elements?
2. What are the symbols of the following elements: hydrogen, nitrogen, magnesium, chlorine, iron, potassium, copper, sulfur, oxygen, phosphorus?
3. Are there more metals or nonmetals among chemical elements? [Hint: use Figure 1-5]
4. Which of the following elements are metals, nonmetals, or metalloids: Si, Na, F, Cl, Ca, B, Br, As, Cu, Fe, P, Mg, B, Ba. [Hint: use Figure 1-5]
5. By replacing the subscripts x, y, and z with numbers, write chemical formulas for the following molecules.
(A) Methane (the major component of natural gas), comprising 1 carbon atom and 4 hydrogen atoms, Cx
. Pronounce the resultant formula. [Answer: CH4
(B) Isopropanol (rubbing alcohol), consisting of 4 carbon atoms, 8 hydrogen atoms, and 1 oxygen atom, Cx
. Pronounce the resultant formula. [Answer: C4
(C) Sucrose (sugar), consisting of 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms, Cx
. Pronounce the resultant formula. [Answer: C12
(D) Iron oxide (rust), consisting of 2 iron atoms and 3 oxygen atoms, Fex
. Pronounce the resultant formula. [Answer: Fe2
(E) A molecule of oxygen comprising two oxygen atoms Ox
and ozone comprising three oxygen atoms, Oy
. Pronounce the resultant formulas. [Answer: O2
; O-two and O-three]