ions

Ionic compounds are written with

• cation (+ ion) first then anion (- ion)
• anion (- ion) first then cation (+ ion)
• either way is fine
• polyatomic ions first

Ba⁺², Br^-1

• BrBa
• Br₂Ba₂
• BaBr₂
• Br₂Ba

Ca⁺², O^-2

• CaO
• OCa
• Ca_-2O₊₂
• Ca₂O₂

Ca⁺²P^-3

• PCa
• P₂Ca₃
• CaP
• Ca₃P₂

When adding a subscript to a polyatomic ion, you should...

• multiply any subscripts on the polyatomic ion by the subscript you are adding
• put parentheses around the polyatomic ion before adding a subscript
• write the new subscript next to any subscripts on the polyatomic ion
• put the polyatomic ion in square brackets before adding the subscript

What is the correct formula for phosphorous trichloride?

• P₃Cl
• PCl₃
• KCl₃
• K₃Cl

What is the correct formula for carbon dioxide?

• C₂O₂
• C₂0
• CO
• CO₂

What is the correct name for SO₂?

• Sulfur oxide
• Sulfite
• Sulfur dioxide
• Sulfur II Oxide

The chemical formula for an ionic compound of aluminum and chlorine is

• AlCl.
• ClAl.
• AlCl₃.
• Al₃Cl.

 Ionic compounds must have...

• a metal and a polyatomic ion
  
• a cation and an anion
• only nonmetals
• only metals