To draw Lewis structures, we focus on the valence electrons of the atoms involved and how they bond to satisfy the octet rule where applicable. Here’s a breakdown of the Lewis structures for H2, HBr, and PCl3.
1. H2 (Hydrogen Molecule)
Each hydrogen atom has one valence electron. When they bond, they share their electrons, resulting in a single covalent bond. The Lewis structure is represented as:
H: H
which can also be shown as H-H for simplicity.
2. HBr (Hydrogen Bromide)
Hydrogen has one valence electron, while bromine has seven. In HBr, hydrogen shares its one electron with bromine to form a covalent bond. The Lewis structure for HBr is:
H: Br
This illustrates that hydrogen has access to two electrons (its own and one from bromine), while bromine effectively has eight electrons surrounding it, satisfying the octet rule.
3. PCl3 (Phosphorus Trichloride)
Phosphorus has five valence electrons, and each chlorine has seven. In PCl3, phosphorus forms three single covalent bonds with three chlorine atoms. The Lewis structure is:
Cl
|
Cl-P-Cl
|
Cl
In this structure, phosphorus contributes its three valence electrons to bond with one electron from each chlorine atom. Chlorine, sharing one of its electrons with phosphorus, effectively completes its octet, while phosphorus has a total of eight electrons around it as well.
Understanding these structures helps visualize how atoms bond and share electrons, providing insight into molecular composition and behavior.