Writing the chemical formula of ionic compounds

Which one of these are polyatomic ions?

• Hydroxide

• Barium

• Ammonium

• Chloride

• Sulfate

Which ones of these are polyatomic ions?

• Carbide

• Carbonate

• Sulfate

• Phosphoride

• Phosphate

What is the chemical formula for magnesium chloride?

• MgCl₂

• Mg_2Cl

• MgCl

• Mg(Cl)₂

• (Mg)₂Cl

Write down the chemical formula for Calcium hydroxide

• CaOH

• (Ca)₂OH

• CaOH₂

• Ca(OH)₂

What is the chemical formula of sodium sulfate

• Na(SO₄)₂

• (Na)₂SO₄

• NaSO₄

• Na₂SO₄

What is the chemical formula of Aluminium iodide?

• AI

• Al₂I

• AlI₃

• ALI₃

What is the chemical formula of oxygen difluoride

• O₂Fl

• OFl₂

• O(Fl)₂

• FlO₂

What is the chemical formula of Ammonia gas?

• NH₄

• NH₃^-

• NH₃

• NH₄^-

To write the chemical formula of ionic compounds, you must know the (a)   of each ion, and balance them out so it becomes a stable compound. For example, Copper (II) chloride is written as CuCl₂

To write covalent compounds, you must look at the (a)   of every element to know the number of atoms in the molecule. e.g Carbon dioxide means the formula is CO₂