Covalent Bonding

Learn the models, terms, and applications of covalent bonding.

Lesson 2 of 32 parts Practice Flashcards

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Covalent Molecules and Lewis Structures

Objective: Count atoms and interpret simple shared-electron diagrams.

Covalent molecules contain atoms connected by shared electron density; a molecular formula counts atoms of each element but does not uniquely reveal bond arrangement. H₂O has two hydrogen atoms and one oxygen atom, while CO₂ has one carbon and two oxygens. Lewis structures represent bonding pairs and lone pairs; a single line commonly represents one shared electron pair. Some molecules have double or triple bonds, and resonance or more advanced electron descriptions may be needed. Molecular shape affects properties: water is bent, not a straight H–O–H arrangement. Avoid treating a flat Lewis sketch as a complete three-dimensional structure.

Worked examples

Try itHow many oxygen atoms are in CO₂?Show answer

1. Identify the relevant concept in this section. 2. The subscript 2 applies to oxygen. 3. Answer: Two

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Covalent Molecules and Lewis Structures

Objective: Count atoms and interpret simple shared-electron diagrams.

Worked examples

Try itHow many oxygen atoms are in CO₂?Show answer

1. Identify the relevant concept in this section. 2. The subscript 2 applies to oxygen. 3. Answer: Two

Applications and Worked Problems

Objective: Apply covalent bonding to calculations, evidence, and specified situations.

A covalent bond involves shared electron density and attraction between electrons and nuclei. In Lewis counting, a single bond is one shared pair, a double bond two pairs, and a triple bond three pairs. Lewis structures distinguish bonding pairs from lone pairs, but they simplify delocalization and quantum behavior. Breaking a bond requires energy; bond formation releases energy. The net reaction energy depends on both breaking reactant bonds and forming product bonds, not on one process alone.

Formulas

single/double/triple bond = 2/4/6 shared electrons

Worked examples

Try itIn a simple Lewis bond model, H2 has a bond of order 1. How many electrons are shared in that bond?Show answer

1. Each covalent bond contains a shared electron pair. 2. 1 pair(s) × 2 = 2 electrons.

Try itThe bond in H2 shares 2 electrons. How many shared pairs is that?Show answer

1. A pair contains two electrons. 2. 2/2 = 1 shared pair(s).

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