How to Write the Chemical Formula

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

Tags

NGSS.HS-PS1-2

Ca⁺², O^-2

• CaO
• OCa
• Ca_-2O₊₂
• Ca₂O₂

Tags

NGSS.HS-PS1-2

Ca⁺²P^-3

• PCa
• P₂Ca₃
• CaP
• Ca₃P₂

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

The correct chemical formula for magnesium phosphide is

• MgP
• Mg₂P₃
• Mg₃P₂
• Mg₃(PO₄)₂

Tags

NGSS.HS-PS1-1

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 do atoms of metals tend to do with their valence electrons when bonding with non-metals?

• share them
• donate them
• keep them and accept others
• keep them and give others

Tags

NGSS.HS-PS1-2

What is the correct formula for phosphorous trichloride?

• P₃Cl
• PCl₃
• KCl₃
• K₃Cl

What is the correct formula for aluminum phosphide?

• Al₃P₃
• AlP
• AlPO₄
• AlPO₃

What is the correct formula for dichlorine monoxide?

• Co₃O
• ClO₂
• Cl₂O
• (Cl₂)₂O