Names Of Covalent Compounds Worksheet

Mastering Covalent Compound Nomenclature: A Comprehensive Worksheet and Guide

Understanding the naming conventions of covalent compounds is crucial for success in chemistry. This worksheet is designed to help you master the naming process, moving from basic binary compounds to more complex structures. We’ll break down the rules, provide plenty of practice problems, and offer explanations to solidify your understanding. This comprehensive guide will help you confidently name and identify covalent compounds, laying a solid foundation for future chemical studies.

Introduction to Covalent Compounds

Covalent compounds are formed when atoms share electrons to achieve a stable electron configuration. Unlike ionic compounds, which involve the transfer of electrons, covalent compounds are characterized by the strong bonds formed through electron sharing. This sharing creates molecules, distinct units of atoms bonded together. Understanding how these molecules are named is key to communicating their composition accurately.

Naming Binary Covalent Compounds: The Basics

The simplest covalent compounds are binary compounds, meaning they consist of only two elements. Naming these compounds follows a specific set of rules:

1. The first element is named first, using its full elemental name.

2. The second element is named using its root name (usually the first few letters) followed by the suffix "-ide".

3. Greek prefixes are used to indicate the number of atoms of each element present in the molecule. These prefixes include:

   • Mono- (1)
   • Di- (2)
   • Tri- (3)
   • Tetra- (4)
   • Penta- (5)
   • Hexa- (6)
   • Hepta- (7)
   • Octa- (8)
   • Nona- (9)
   • Deca- (10)

4. The prefix "mono-" is generally omitted for the first element unless it's needed to distinguish between different compounds. For example, CO is carbon monoxide, not carbon oxide.

Example: CO₂ is named carbon dioxide. The prefix "di-" indicates two oxygen atoms.

Practice Problems: Binary Covalent Compounds

Let's test your understanding with some practice problems. Name the following binary covalent compounds:

1. SO₂
2. N₂O₄
3. PCl₅
4. SF₆
5. Cl₂O₇
6. BrF₃
7. SiH₄
8. B₂H₆
9. AsCl₃
10. CO

Answers:

1. Sulfur dioxide
2. Dinitrogen tetroxide
3. Phosphorus pentachloride
4. Sulfur hexafluoride
5. Dichlorine heptoxide
6. Bromine trifluoride
7. Silicon tetrahydride
8. Diboron hexahydride
9. Arsenic trichloride
10. Carbon monoxide

Naming Covalent Compounds with More Than Two Elements

Naming covalent compounds with more than two elements becomes more complex but follows a logical extension of the binary naming rules. The key is to systematically name each element and its corresponding number of atoms using the appropriate prefixes. Remember that the order of elements generally follows the electronegativity trend. The least electronegative element is usually named first.

Example: P₄O₁₀ is named tetraphosphorus decoxide.

Practice Problems: Multi-Element Covalent Compounds

Let’s tackle some more challenging examples. Name the following compounds:

1. N₂O₅
2. PCl₃
3. SO₃
4. CS₂
5. Si₂H₆
6. IF₇
7. XeF₄
8. P₄S₃
9. B₂O₃
10. Cl₂O

Answers:

1. Dinitrogen pentoxide
2. Phosphorus trichloride
3. Sulfur trioxide
4. Carbon disulfide
5. Disilane
6. Iodine heptafluoride
7. Xenon tetrafluoride
8. Tetraphosphorus trisulfide
9. Diboron trioxide
10. Dichlorine monoxide

Acids: A Special Case of Covalent Compounds

Acids are a special category of covalent compounds that release hydrogen ions (H⁺) when dissolved in water. Their naming conventions differ slightly from the general rules:

• Binary acids: These contain hydrogen and a nonmetal. They are named using the prefix "hydro-" followed by the root name of the nonmetal and the suffix "-ic acid". For example, HCl is hydrochloric acid.

• Oxyacids: These contain hydrogen, a nonmetal, and oxygen. Their naming is more complex and depends on the oxidation state of the nonmetal. The most common oxyacids are named by changing the suffix of the nonmetal’s name as follows:

  • If the nonmetal's root ends in "-ate" (e.g., sulfate), the acid's name ends in "-ic acid". Example: H₂SO₄ is sulfuric acid.
  • If the nonmetal's root ends in "-ite" (e.g., sulfite), the acid's name ends in "-ous acid". Example: H₂SO₃ is sulfurous acid.

Practice Problems: Acids

Name the following acids:

1. HF
2. HBr
3. H₂S
4. HNO₃
5. HNO₂
6. H₃PO₄
7. H₂CO₃
8. HClO₄
9. H₂SO₃
10. HBrO

Answers:

1. Hydrofluoric acid
2. Hydrobromic acid
3. Hydrosulfuric acid
4. Nitric acid
5. Nitrous acid
6. Phosphoric acid
7. Carbonic acid
8. Perchloric acid
9. Sulfurous acid
10. Hypobromous acid

Advanced Covalent Compound Nomenclature: Polyatomic Ions

Many covalent compounds incorporate polyatomic ions – groups of atoms that carry a charge and behave as a single unit. Naming these compounds requires knowing the names and charges of common polyatomic ions.

Example: Ammonium nitrate (NH₄NO₃) contains the ammonium ion (NH₄⁺) and the nitrate ion (NO₃⁻).

Practice Problems: Compounds with Polyatomic Ions

Name the following compounds containing polyatomic ions:

1. Na₂SO₄
2. KNO₃
3. Ca(OH)₂
4. (NH₄)₂CO₃
5. Mg₃(PO₄)₂
6. Al₂(SO₄)₃
7. Fe(NO₃)₃
8. CuSO₄
9. ZnCO₃
10. NH₄Cl

Answers:

1. Sodium sulfate
2. Potassium nitrate
3. Calcium hydroxide
4. Ammonium carbonate
5. Magnesium phosphate
6. Aluminum sulfate
7. Iron(III) nitrate
8. Copper(II) sulfate
9. Zinc carbonate
10. Ammonium chloride

Understanding Oxidation States

The oxidation state of an atom represents its apparent charge within a molecule or ion. While not directly used in naming simple covalent compounds, understanding oxidation states is crucial for naming more complex ones, particularly those involving transition metals and polyatomic ions.

Frequently Asked Questions (FAQ)

Q: What is the difference between covalent and ionic compounds?

A: Covalent compounds are formed through the sharing of electrons between atoms, while ionic compounds are formed through the transfer of electrons, resulting in the formation of ions with opposite charges.

Q: Why are prefixes used in naming covalent compounds but not ionic compounds?

A: Prefixes are used in covalent compounds to indicate the specific number of each type of atom in the molecule, as the ratio of atoms can vary greatly. In ionic compounds, the ratio is typically fixed by the charges of the ions.

Q: What if I encounter a compound I don't recognize?

A: Refer to a periodic table and a list of common polyatomic ions to determine the elements present and their potential oxidation states. Use this information to deduce the appropriate name following the rules outlined above. Consult a chemistry textbook or online resource for further assistance.

Conclusion

Mastering covalent compound nomenclature requires practice and a systematic approach. By understanding the fundamental rules, practicing with diverse examples, and familiarizing yourself with common polyatomic ions, you will build a strong foundation in chemical naming conventions. Remember that consistent practice is key to success. Use this worksheet as a tool for self-assessment and continue to challenge yourself with increasingly complex examples. With dedicated effort, you’ll confidently navigate the world of covalent compound nomenclature.