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Ch.2 - Atoms, Molecules, and Ions
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232Not the one you use?Change textbook
All textbooksBrown 14th EditionCh.2 - Atoms, Molecules, and IonsProblem 65a
Chapter 2, Problem 65a

Predict whether each of the following compounds is molecular or ionic: (a) HClO4

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1
Identify the types of elements involved in the compound HClO_4. Hydrogen (H) and chlorine (Cl) are nonmetals, and oxygen (O) is also a nonmetal.
Recall that molecular compounds are typically formed between nonmetals, while ionic compounds are formed between metals and nonmetals.
Consider the nature of the bonds in HClO_4. Since it consists of nonmetals, it is likely to form covalent bonds, which are characteristic of molecular compounds.
Recognize that HClO_4 is known as perchloric acid, which is a common example of a molecular compound.
Conclude that HClO_4 is a molecular compound because it is composed entirely of nonmetals and forms covalent bonds.

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Key Concepts

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

Ionic vs. Molecular Compounds

Ionic compounds are formed from the electrostatic attraction between positively and negatively charged ions, typically involving a metal and a nonmetal. In contrast, molecular compounds consist of molecules formed by covalent bonds, where atoms share electrons, usually involving nonmetals. Understanding the distinction helps in predicting the properties and behaviors of different compounds.
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Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond. In a compound, if there is a significant difference in electronegativity between the bonded atoms, the bond is likely ionic. If the difference is small, the bond is typically covalent, indicating a molecular compound.
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Common Molecular and Ionic Compounds

Certain compounds are commonly recognized as either ionic or molecular based on their composition. For example, compounds like HClO4 (perchloric acid) are molecular because they consist of nonmetals and exhibit covalent bonding. Familiarity with common examples aids in quickly classifying new compounds based on their chemical formulas.
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Related Practice
Textbook Question

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