Mastering Formulas for Compounds with Polyatomic Ions

The video tutorial explains how to write chemical formulas for compounds containing polyatomic ions. It covers the use of the periodic table and common ion tables to identify elements and their charges. The tutorial demonstrates the process with examples like potassium nitrate, sodium phosphate, calcium phosphite, magnesium phosphate, and ammonium carbonate. It introduces the criss-cross method for balancing charges and emphasizes the importance of understanding polyatomic ions as single entities. The video encourages memorizing common polyatomic ions for efficiency.

What is the charge of potassium when forming compounds with polyatomic ions?

• +1

• +2

• -2

• -1

Which of the following is the correct formula for potassium nitrate?

• K3NO

• K2NO3

• KNO2

• KNO3

What is the charge of sodium in sodium phosphate?

• +1

• -1

• +2

• -2

How many sodium ions are needed to balance the charge of one phosphate ion in sodium phosphate?

• 1

• 2

• 3

• 4

What is the correct formula for sodium phosphate?

• NaPO4

• Na2PO4

• Na4PO4

• Na3PO4

What method is used to balance charges in calcium phosphite?

• Cross-multiplication

• Addition

• Criss-cross method

• Substitution

What is the charge of calcium in calcium phosphite?

• +1

• +2

• -1

• -2

Which of the following is the correct formula for calcium phosphite?

• Ca(PO3)2

• CaPO3

• Ca2(PO3)3

• Ca3(PO3)2

What is the charge of ammonium in ammonium carbonate?

• -1

• +1

• -2

• +2

Which of the following is the correct formula for ammonium carbonate?

• NH4(CO3)2

• (NH4)2CO3

• (NH4)3CO3

• NH4CO3