Step-by-Step Guidance for Naming and Writing Chemical Compounds

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Q1. Name each of the following monatomic cations:

Background

Topic: Naming Monatomic Cations

This question tests your understanding of how to name positively charged ions (cations) formed from metals, including those that form only one type of ion and those that can form multiple ions (using the Stock system).

Key Terms and Rules:

Monatomic cation: An ion formed from a single atom with a positive charge.
Stock system: Used for metals that can form more than one ion; the charge is indicated in Roman numerals in parentheses.
Group IA, IIA, IIIA, Ag, Zn: These elements form only one type of ion, named as "element name + ion" (e.g., sodium ion).

Step-by-Step Guidance

Identify the element symbol and its charge for each ion (e.g., Li+, Ba2+).
Determine if the element is from Group IA, IIA, IIIA, Ag, or Zn. If so, use the format: element name + ion (e.g., Na+ = sodium ion).
If the element is a transition metal or can form more than one ion (e.g., Fe, Cu, Sn), use the Stock system: element name (charge in Roman numerals) + ion (e.g., Fe2+ = iron (II) ion).
Write the correct name for each cation based on the rules above.

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Q2. Name each of the following monatomic anions:

Background

Topic: Naming Monatomic Anions

This question tests your ability to name negatively charged ions (anions) formed from nonmetals.

Key Terms and Rules:

Monatomic anion: An ion formed from a single nonmetal atom with a negative charge.
Naming rule: Use the stem of the element name + "ide" + ion (e.g., O2− = oxide ion).

Step-by-Step Guidance

Identify the element symbol and its charge for each anion (e.g., F−, S2−).
Take the stem of the element's name and add the suffix "-ide" followed by "ion" (e.g., Cl− = chloride ion).
Write the correct name for each anion using this rule.

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Q3. Name each of the following polyatomic ions:

Background

Topic: Naming Polyatomic Ions

This question tests your knowledge of common polyatomic ions and their names.

Key Terms and Examples:

Polyatomic ion: An ion composed of two or more atoms covalently bonded, carrying a net charge.
Examples: NH4+ = ammonium ion, SO42− = sulfate ion.

Step-by-Step Guidance

Identify the formula of each polyatomic ion (e.g., NO3−, PO43−).
Recall or refer to a table of common polyatomic ions to match each formula with its correct name.
Write the name for each ion (e.g., NO3− = nitrate ion).

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Q4. Combine each pair of ions to get the formula of the compound they form (equal and opposite charges):

Background

Topic: Writing Chemical Formulas from Ions

This question tests your ability to write the correct chemical formula for ionic compounds formed from ions with equal and opposite charges.

Key Terms and Rules:

Ionic compound: A compound composed of cations and anions in a ratio that results in overall neutrality.
Rule: If the charges are equal and opposite, the formula contains one of each ion (e.g., Na+ + Cl− → NaCl).

Step-by-Step Guidance

Write the symbols and charges for each ion in the pair.
Check if the charges are numerically equal and opposite (e.g., +1 and -1, +2 and -2).
If so, write the formula with one of each ion (e.g., NH4+ + F− → NH4F).
If a polyatomic ion is present, use parentheses only if more than one is needed (not in this case).

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Q5. Combine each pair of ions to get the formula of the compound they form (different charges):

Background

Topic: Writing Chemical Formulas Using the Crossover Rule

This question tests your ability to use the crossover rule to write formulas for ionic compounds when the ions have different charges.

Key Terms and Rules:

Crossover rule: The magnitude of the charge on each ion becomes the subscript for the other ion (without the sign).
Parentheses: Use parentheses around polyatomic ions if more than one is needed.
Simplify: Reduce subscripts to the lowest whole-number ratio if possible.

Step-by-Step Guidance

Write the symbols and charges for each ion in the pair (e.g., Cu+ and O2−).
Apply the crossover rule: the charge number of the cation becomes the subscript for the anion, and vice versa.
Write the formula, using parentheses for polyatomic ions if more than one is needed (e.g., (NH4)2O).
Simplify the subscripts to the lowest ratio if possible.

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Q6. Combine each pair of ions to get the chemical formula, then name the compound:

Background

Topic: Naming Ionic Compounds from Ions

This question tests your ability to write the formula for an ionic compound from its ions and then name the compound correctly.

Key Terms and Rules:

Ionic compound: Made from a cation and an anion; the formula must be neutral.
Naming: Name the cation first, then the anion (drop the word "ion"). For transition metals, use the Stock system.

Step-by-Step Guidance

Write the chemical formula for the compound using the crossover rule if needed.
Name the cation (include Roman numerals if it's a transition metal with multiple possible charges).
Name the anion (use "-ide" for monatomic anions, or the polyatomic ion name).
Combine the names to get the full compound name.

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Q7. Give the name for each compound given its chemical formula:

Background

Topic: Naming Ionic Compounds from Formulas

This question tests your ability to identify the ions in a compound and name the compound correctly, including using the Stock system for transition metals.

Key Terms and Rules:

Identify cation and anion: Break down the formula into its ions.
Naming: Name the cation (with Roman numeral if needed), then the anion.
Polyatomic ions: Use the correct polyatomic ion name if present.

Step-by-Step Guidance

Identify the cation and anion in the formula (e.g., MgCl2: Mg2+ and Cl−).
Determine the charge on the cation if it's a transition metal (use the anion's charge and the formula's subscripts).
Name the cation and anion, then combine them to name the compound.

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Q8. Give the chemical formula for each compound given its name:

Background

Topic: Writing Chemical Formulas from Compound Names

This question tests your ability to determine the correct ions from a compound's name and write the chemical formula using the crossover rule.

Key Terms and Rules:

Cation and anion: Identify the ions from the compound name.
Crossover rule: Use the charges to determine the subscripts in the formula.
Parentheses: Use parentheses for polyatomic ions if more than one is needed.

Step-by-Step Guidance

Identify the cation and anion from the compound name (e.g., iron (III) sulfate: Fe3+ and SO42−).
Write the symbols and charges for each ion.
Apply the crossover rule to determine the subscripts for each ion in the formula.
Write the chemical formula, using parentheses for polyatomic ions if necessary.

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Q9. Name the following molecular compounds:

Background

Topic: Naming Molecular (Covalent) Compounds

This question tests your ability to use Greek prefixes to indicate the number of atoms of each element in a molecular compound.

Key Terms and Rules:

Molecular compound: Composed of nonmetals bonded covalently.
Greek prefixes: Indicate the number of atoms (e.g., di-, tri-, tetra-).
Naming: Prefix + element name for the first element; prefix + stem + "-ide" for the second element.

Step-by-Step Guidance

Count the number of atoms of each element in the formula.
Assign the correct Greek prefix to each element (omit "mono-" for the first element).
Name the first element with its full name and the second with the stem + "-ide" ending.

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Q10. Give the formulas for each of the following molecular compounds:

Background

Topic: Writing Formulas for Molecular Compounds

This question tests your ability to use Greek prefixes in the compound name to write the correct chemical formula.

Key Terms and Rules:

Greek prefixes: Indicate the number of atoms of each element.
Formula: Write the symbol for each element, using the prefix to determine the subscript.

Step-by-Step Guidance

Identify the elements and the number of atoms of each from the name (e.g., dinitrogen pentasulfide: N = 2, S = 5).
Write the chemical formula using the correct subscripts for each element.

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Q11. Name each of the following ions, and determine the formula and name of the corresponding acid that forms from the ion:

Background

Topic: Naming Acids from Ions

This question tests your ability to name anions, write the formula for the acid formed by adding H atoms equal to the negative charge, and name the acid based on the anion's name.

Key Terms and Rules:

Acid formula: Add H atoms equal to the negative charge of the anion (e.g., SO42− → H2SO4).
Naming acids: If the anion ends in "-ide", use "hydro-...ic acid"; if "-ate", use "...ic acid"; if "-ite", use "...ous acid".

Step-by-Step Guidance

Name the anion (e.g., Cl− = chloride ion).
Add H atoms equal to the negative charge to write the acid formula (e.g., Cl− → HCl).
Name the acid using the appropriate naming rule based on the anion's ending.

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Q12. Name each of the following acids:

Background

Topic: Naming Acids from Formulas

This question tests your ability to name acids given their chemical formulas, using the rules for acids derived from different types of anions.

Key Terms and Rules:

Acid naming: If the anion ends in "-ide", use "hydro-...ic acid"; if "-ate", use "...ic acid"; if "-ite", use "...ous acid".
Recognize polyatomic ions: Identify the anion in the acid formula to apply the correct naming rule.

Step-by-Step Guidance

Identify the anion in each acid formula (e.g., HBr: Br−).
Determine the name of the anion and apply the correct acid naming rule.
Write the name of the acid accordingly.

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Q13. Give the formula for each of the following acids:

Background

Topic: Writing Acid Formulas from Names

This question tests your ability to write the correct chemical formula for an acid given its name, using the rules for acids derived from different types of anions.

Key Terms and Rules:

Acid formula: Identify the anion from the acid name, then add H atoms equal to the negative charge.
State: Remember to indicate (aq) for aqueous solutions.

Step-by-Step Guidance

Identify the anion from the acid name (e.g., phosphoric acid → phosphate ion, PO43−).
Add H atoms equal to the negative charge to write the acid formula (e.g., H3PO4).
Write the formula and include (aq) to indicate aqueous solution.

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Q14. Name each of the following compounds (mixed review):

Background

Topic: Naming Compounds (Ionic, Molecular, and Acids)

This question tests your ability to identify and name a variety of compounds, including ionic compounds, molecular compounds, and acids, using the appropriate rules for each type.

Key Terms and Rules:

Ionic compounds: Name the cation (with Roman numeral if needed), then the anion.
Molecular compounds: Use Greek prefixes to indicate the number of atoms.
Acids: Use the appropriate acid naming rule based on the anion.

Step-by-Step Guidance

Identify the type of compound (ionic, molecular, or acid) based on the formula.
Apply the correct naming rules for that type of compound.
Write the name of the compound accordingly.