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

Verified step by step guidance

1. Determine the number of valence electrons in sulfur. Sulfur has an atomic number of 16, which means it has 16 electrons. The electron configuration of sulfur is 1s^2 2s^2 2p^6 3s^2 3p^4. The electrons in the outermost shell (3s^2 3p^4) are the valence electrons, totaling 6.
2. Understand that hydrogen has 1 valence electron and needs 1 more electron to complete its outer shell and achieve a stable configuration.
3. Recognize that sulfur needs 2 more electrons to complete its outer shell (to make a total of 8 valence electrons, fulfilling the octet rule).
4. Predict the bonding: Sulfur can share two of its valence electrons with two hydrogen atoms, forming two single covalent bonds. Each hydrogen shares its one electron with sulfur, thus each hydrogen achieves a full shell by having 2 electrons, and sulfur achieves a full shell by having 8 electrons in its valence shell.
5. Conclude the molecular formula: Since each sulfur atom bonds with two hydrogen atoms, the molecular formula of the compound is H2S.

Key Concepts

Atomic Number and Valence Electrons

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. Valence electrons are crucial for determining how an atom will bond with others, as they are involved in forming chemical bonds.

Covalent Bonding

Covalent bonding occurs when two atoms share one or more pairs of electrons to achieve a full outer electron shell, leading to greater stability. In the case of hydrogen sulfide (H2S), sulfur shares its valence electrons with two hydrogen atoms, allowing each atom to attain a stable electron configuration. This type of bonding is common in molecular compounds.

Molecular Formula

A molecular formula represents the number and types of atoms in a molecule. For hydrogen sulfide, the molecular formula is H2S, indicating that each molecule consists of two hydrogen atoms and one sulfur atom. Understanding how to derive the molecular formula from the bonding behavior and valence electrons of the constituent atoms is essential for predicting chemical compounds.