Chemistry - Chapter 9

Cations

• Positively charged ions

• Named the same as the parent element

Anions

• Negatively charged ions from gaining electrons

• Naming Anions: Drop the last part of the element’s name and replace it with “-ide”

Stock System

• Used for ionic compounds with transition metals

• Uses Roman numerals in parentheses after the metal to show the charge

• The charge is represented in Roman numerals through the subscript

• Roman numerals are only used for cations

Transition metals with one charge

• Silver: +1

• Cadmium: +2

• Zinc: +2

• These metals do not use Roman numerals

Polyatomic Ions

• Consists of more than one atom but behaves as a single charged unit.

• Most names end in –ite or –ate

• Difference: -ite has one less atom than -ate.

Monatomic ions

• Ions consisting of a single atom with a positive or negative charge.

• Formed when atoms gain or lose electrons to become stable through a full octet

hydrogen ____ ion

A hydrogen ion added to a polyatomic ion

Binary Ionic Compounds

• A compound made up of a cation and an anion

• First, write the symbol of the cation

• Then, write the symbol of the anion

• Add subscripts to balance the charges (criss-cross method)

• If there is the same charge number for the anion and cation, simplify to the lowest whole number ratio

Writing formulas for compounds with polyatomic ions

• First, write the symbol of the cation
  Then write the symbol of the anion

• Use the criss-cross method to balance the equation

• Put the polyatomic ion parentheses before the subscript if needed

Binary molecular compounds

• First, use the number prefixes before the element name

• List it from cation to anion

Acid

• A compound that has at least one hydrogen ion (H⁺)

• Produces water and salt in a reaction

Acid naming steps

An anion is combined with as many hydrogen (H⁺) ions to make the equation neutral

Generic acid formula

H_nX

X: monatomic/polyatomic

n: amount of H ions

3 basic acid naming rules

• ends in -ide: acid begins with hydro, ends with -ic

• ends in -ate: acid ends with -ic

• ends in -ite: acid ends with -ous

Base

• An ionic compound that produces hydroxide when dissolved in water

• Named by listing the cation, then the anion