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.

Try solving on your own before revealing the answer!

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.

Try solving on your own before revealing the answer!

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 List:

Polyatomic ion: An ion composed of two or more atoms covalently bonded, carrying a charge.
Common examples: NH4+ (ammonium), SO42– (sulfate), NO3– (nitrate), etc.

Step-by-Step Guidance

Match each formula to its corresponding name from the provided table or your memory (e.g., CN– = cyanide ion).
Be careful with similar formulas (e.g., SO42– vs. SO32–).
Write the correct name for each polyatomic ion.

Try solving on your own before revealing the answer!

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, ensuring the total positive and negative charges balance to zero.

Key Terms and Rules:

Ionic compound: Made of cations and anions; the formula must be electrically neutral.
Rule: If the charges are equal and opposite, use 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 (no subscripts needed).
If a polyatomic ion is present, write it as a unit (e.g., NH4F).

Try solving on your own before revealing the answer!

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

Background

Topic: Writing Chemical Formulas Using the Crossover Rule

This question tests your ability to apply 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 (ignore the sign).
Polyatomic ions: If more than one is needed, use parentheses around the polyatomic ion.
Simplify: Reduce subscripts to the lowest whole-number ratio if possible.

Step-by-Step Guidance

Write the symbols and charges for each ion.
Apply the crossover rule: the charge number of the cation becomes the subscript for the anion, and vice versa.
If a polyatomic ion needs a subscript greater than one, use parentheses (e.g., (SO4)2).
Simplify the subscripts to the lowest ratio if possible.

Try solving on your own before revealing the answer!

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:

Cation: Name the metal ion first (use Stock system if necessary).
Anion: Name the nonmetal or polyatomic ion second.
Formula: Use the crossover rule to balance charges.

Step-by-Step Guidance

Write the correct formula for the compound using the crossover rule.
Name the cation (include Roman numeral if the metal can have more than one charge).
Name the anion (use "-ide" for monatomic, or the polyatomic ion's name).
Combine the names in the correct order: cation name + anion name.

Try solving on your own before revealing the answer!

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.
Stock system: Use Roman numerals for metals with variable charges.
Polyatomic ions: Recognize and name them correctly.

Step-by-Step Guidance

Identify the cation and anion in the formula.
Determine the charge on the cation (especially for transition metals).
Name the cation (with Roman numeral if needed) and the anion.
Combine the names in the correct order.

Try solving on your own before revealing the answer!

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 formula using the crossover rule.

Key Terms and Rules:

Identify ions: Use the name to determine the cation and anion (and their charges).
Crossover rule: Balance the charges to write the correct formula.
Polyatomic ions: Use parentheses if more than one is needed.

Step-by-Step Guidance

Identify the cation and anion (and their charges) from the compound name.
Apply the crossover rule to determine the subscripts for each ion.
Write the formula, using parentheses for polyatomic ions if necessary.

Try solving on your own before revealing the answer!

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: Made of nonmetals bonded covalently.
Greek prefixes: mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-.
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).
Write the name: [prefix][element name] [prefix][stem of second element + "-ide"].

Try solving on your own before revealing the answer!

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

Background

Topic: Writing Formulas for Molecular Compounds

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

Key Terms and Rules:

Greek prefixes: Indicate the number of atoms of each element.
Formula: Use the element symbols and the numbers from the prefixes.

Step-by-Step Guidance

Identify the elements and the number of atoms of each from the name and prefixes.
Write the chemical formula using the correct subscripts for each element.

Try solving on your own before revealing the answer!

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 corresponding acid, and name the acid based on the anion's name and charge.

Key Terms and Rules:

Acid formula: Add enough H+ ions to balance the negative charge of the anion.
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).
Write the acid formula by adding H atoms equal to the negative charge (e.g., Cl– → HCl).
Name the acid using the appropriate rule based on the anion's suffix.

Try solving on your own before revealing the answer!

Q12. Name each of the following acids:

Background

Topic: Naming Acids from Formulas

This question tests your ability to recognize the formula of an acid and name it according to the rules for binary and oxyacids.

Key Terms and Rules:

Binary acids: H + nonmetal (e.g., HCl, HF) → "hydro-...ic acid".
Oxyacids: H + polyatomic ion (e.g., HNO3, H2SO4) → "...ic acid" or "...ous acid" depending on the ion.

Step-by-Step Guidance

Identify the anion in the acid formula.
Determine if the acid is binary or an oxyacid.
Name the acid using the correct rule for its type.

Try solving on your own before revealing the answer!

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 based on its name, using the rules for binary and oxyacids.

Key Terms and Rules:

Binary acids: "hydro-...ic acid" → H + nonmetal (e.g., hydroiodic acid = HI).
Oxyacids: "...ic acid" or "...ous acid" → H + polyatomic ion (e.g., sulfurous acid = H2SO3).
Balance: Add enough H+ to balance the negative charge of the anion.

Step-by-Step Guidance

Identify the anion from the acid name (e.g., phosphoric acid → phosphate ion).
Write the formula for the acid by adding H atoms equal to the negative charge of the anion.
Include (aq) to indicate the acid is aqueous.

Try solving on your own before revealing the answer!

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 all the rules you've learned.

Key Terms and Rules:

Ionic compounds: Name cation (with Roman numeral if needed) + anion.
Molecular compounds: Use Greek prefixes for both elements.
Acids: Use the rules for binary and oxyacids.

Step-by-Step Guidance

Identify the type of compound (ionic, molecular, or acid) based on its formula.
Break down the formula into its ions or elements as appropriate.
Apply the correct naming rules for that type of compound.
Write the name in the correct format.