The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound. a. HS b. HS2 c. H2S d. H4S

The atomic number of an element indicates the number of protons in its nucleus, which also equals the number of electrons in a neutral atom. For sulfur, with an atomic number of 16, it has six valence electrons in its outer shell. Understanding valence electrons is crucial for predicting how atoms bond and form compounds.

Covalent bonding occurs when two atoms share one or more pairs of electrons to achieve a full outer shell, leading to greater stability. In the case of sulfur and hydrogen, sulfur shares its valence electrons with hydrogen atoms to form hydrogen sulfide. Recognizing how many bonds can be formed based on valence electrons is essential for determining the correct molecular formula.

A molecular formula represents the number and types of atoms in a molecule. For hydrogen sulfide, the correct molecular formula is H2S, indicating that two hydrogen atoms bond with one sulfur atom. Understanding how to derive the molecular formula from the bonding patterns and valence electrons is key to answering the question.