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Ch.6 Ionic and Molecular Compounds
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 6, Problem 102c

State the number of valence electrons, bonding pairs, and lone pairs in each of the following Lewis structures:
c. Lewis structure of BrOBr showing bonding pairs and lone pairs of electrons around the bromine and oxygen atoms.

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1
Step 1: Identify the central atom in the Lewis structure. In this case, phosphorus (P) is the central atom surrounded by three hydrogen (H) atoms and lone pairs of electrons.
Step 2: Count the total number of valence electrons for the molecule. Phosphorus (P) has 5 valence electrons, and each hydrogen (H) has 1 valence electron. The total is 5 + (3 × 1) = 8 valence electrons.
Step 3: Determine the number of bonding pairs. Each hydrogen atom forms a single covalent bond with phosphorus. Since there are three hydrogen atoms, there are 3 bonding pairs.
Step 4: Determine the number of lone pairs on the central atom. After forming three bonds, phosphorus has 2 electrons left, which form one lone pair.
Step 5: Summarize the findings: The molecule has 8 valence electrons, 3 bonding pairs, and 1 lone pair on the central atom.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Valence Electrons

Valence electrons are the outermost electrons of an atom and are crucial for determining how an atom can bond with others. In the case of phosphine (PH3), phosphorus has five valence electrons, while each hydrogen atom has one, leading to a total of eight valence electrons in the molecule.
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Bonding Pairs

Bonding pairs refer to pairs of electrons that are shared between atoms to form covalent bonds. In the Lewis structure of phosphine, there are three bonding pairs formed between the phosphorus atom and the three hydrogen atoms, indicating that each hydrogen shares one electron with phosphorus.
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Lone Pairs

Lone pairs are pairs of valence electrons that are not involved in bonding and remain on the atom. In phosphine, phosphorus has one lone pair of electrons, which influences the molecule's geometry and reactivity, contributing to its trigonal pyramidal shape.
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