Element, Compound, Equation

Which of the following is an example of an element?

• Water (H2O)

• Carbon dioxide (CO2)

• Oxygen (O2)

• Table salt (NaCl)

What is the chemical formula for table salt?

• H2O

• CO2

• O2

• NaCl

Which of the following is a compound?

• Iron (Fe)

• Hydrogen (H)

• Sodium chloride (NaCl)

• Helium (He)

What is the valency of chlorine (Cl)?

• 1

• 2

• 3

• 4

What is the valency of oxygen (O)?

• 1

• 6

• 2

• 3

What is the valency of nitrogen (N)?

• 1

• 2

• 3

• 5

What is the valency of calcium (Ca)?

• 2

• 3

• 3

• 1

What is the formula for sodium chloride?

• NaCl2

• Na2Cl

• NaCl

• Na2Cl2

What is the formula of sodium carbonate

• Na₂CO₃

• NaCO₃

• Na₂CO

• NaCO

What is the chemical formula of Ammonium chloride?

• NH₃Cl

• NHCl

• NH₄Cl

• NH₂Cl