Chemistry Unit 4 - Chapter 7 (Nomenclature)

Questions and Answers

What does nomenclature mean?

naming system

What is the procedure for naming ionic compounds?

Name the cation; if the charge on the cation can vary, write the charge in parentheses as a Roman numeral; drop the last syllable of the anion and replace it with '-ide' or name the polyatomic ion without changing the last syllable.

What does a compound's charge always have to be?

What do the Roman numerals represent in ionic compounds?

The charge on the first ion, usually the metal. Signup and view all the answers

How do you make sure the compounds are balanced?

Using the criss-cross method to balance the charges. Signup and view all the answers

In which order are ionic compounds with transition and post-transition metals always written?

The metal is written first, followed by the cation and then the anion. Signup and view all the answers

What is true about all elements in group 1?

They will all form ions with a +1 charge. Signup and view all the answers

What is true about all elements in group 2?

They will all form ions with a +2 charge. Signup and view all the answers

What is true about aluminum?

It will always form a +3 charge. Signup and view all the answers

What is true about silver?

It will always form a +1 charge. Signup and view all the answers

What is true about cadmium and zinc?

They will always form a +2 ion. Signup and view all the answers

What is true about all elements in group 17?

They will form ions with a -1 charge. Signup and view all the answers

What is true about sulfur, oxygen, and selenium?

They will all form ions with a -2 charge. Signup and view all the answers

What is true about nitrogen and phosphorus?

They will form ions with a -3 charge. Signup and view all the answers

Summarize the cation exceptions to the Roman numerals.

Ag+1 -> silver always forms a +1 cation; Zn+2 -> zinc always forms a +2 cation; Cd+2 -> cadmium always forms a +2 cation; Sn can form both Sn+2 and Sn+4, and Pb can form both Pb+2 and Pb+4. Signup and view all the answers

Match the following prefixes for covalent/molecular compounds:

1 = mono 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa 7 = hepta 8 = octa 9 = nona 10 = deca Signup and view all the answers

How are simple cations named?

By saying the element and adding the word 'ion'. Signup and view all the answers

How are simple anions named?

By dropping the ending off the element name and adding 'ide'. Signup and view all the answers

How do you figure out the charge of a monatomic anion?

The charge is equal to the group number minus 18. Signup and view all the answers

What is hydride?

H-1, only when reacting with metals. Signup and view all the answers

What is the hydrogen ion?

H+1 Signup and view all the answers

What are ionic compounds?

Compounds formed by the combination of a cation and an anion. Signup and view all the answers

When writing formulas for ionic compounds, how does one denote the amount of each atom contained in the compound?

The subscripts indicate how many of each atom is contained in the compound. Signup and view all the answers

What to remember about ionic compounds?

Ionic compounds must be neutral; the charges must cancel out to a net charge of 0. Signup and view all the answers

Review: how does one name an ionic compound?

Write the element name of the metal followed by the ion name of the nonmetal. Signup and view all the answers

What is a polyatomic ion?

Polyatomic ions contain two or more different atoms. Signup and view all the answers

Study Notes

Nomenclature Overview

Nomenclature refers to the system of naming compounds in chemistry.

Naming Ionic Compounds

Name the cation first; if the cation's charge varies, use Roman numerals to indicate the charge.
For anions, change the suffix to "-ide" unless it's a polyatomic ion; in that case, just use its name.
Example: MgCl₂ is named magnesium chloride, while FeCO₃ is iron (II) carbonate.

Charge of Compounds

Compounds must have an overall charge of zero; charges must balance.

Roman Numerals in Ionic Compounds

Roman numerals indicate the charge of the cation (metal); essential for metals with variable charges.

Balancing Compounds

Use the criss-cross method to ensure charge balance: the charge (disregarding the sign) of one ion becomes the subscript of the other.

Order of Written Ionic Compounds

In ionic compounds, the metal (cation) is always listed first, followed by the anion.

Element Charges

Group 1 elements form ions with a +1 charge.
Group 2 elements form ions with a +2 charge.
Aluminum always forms a +3 charge.
Silver always forms a +1 charge.
Cadmium and zinc consistently form +2 ions.
Group 17 elements generate ions with a -1 charge.
Sulfur, oxygen, and selenium form ions with a -2 charge.
Nitrogen and phosphorus form ions with a -3 charge.

Exceptions to Roman Numerals

Silver (Ag⁺) and zinc (Zn²⁺) always have fixed charges and do not need Roman numerals.
Cadmium (Cd²⁺) also has a fixed charge.
Tin (Sn) can have Sn²⁺ or Sn⁴⁺, and lead (Pb) can be Pb²⁺ or Pb⁴⁺, requiring Roman numerals.

Covalent/Molecular Compound Prefixes

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

Naming Cations and Anions

Simple cations are named by stating the element plus "ion" (e.g., Na⁺ is sodium ion).
Simple anions drop the suffix and add "ide" (e.g., F⁻ is fluoride).

Charge of Monatomic Anions

The charge equals the group number minus 18.

Special Ions

Hydride (H⁻) is formed only when reacting with metals.
The hydrogen ion is represented as H⁺.

Ionic Compounds

Formed from a cation and an anion, commonly referred to as "salts."
Binary ionic compounds contain only two elements.

Writing Formulas for Ionic Compounds

Subscripts indicate the number of each atom present in the compound.

Key Aspects of Ionic Compounds

Despite ion charges, ionic compounds must be neutral.
The combined charges of the cation and anion should total zero.

Naming Ionic Compounds Summary

The metal's name comes first, followed by the nonmetal’s ion name.
Example: NaCl is named sodium chloride; CaCl₂ is calcium chloride.

Polyatomic Ions

Comprise two or more different atoms.

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Description

This quiz covers the fundamental concepts of nomenclature in chemistry, focusing on the naming procedures for ionic compounds. Learn to apply the correct naming conventions and understand the significance of cations and anions. Perfect for students aiming to master Unit 4's key terms and definitions.