Daily Assessment on Atoms and Compounds

Which of the following is an element?

• Water

• Carbon dioxide

• Hydrogen

• Salt

Which one is a compound?

• Nitrogen

• Salt

• Air

• Iron

Which statement is TRUE about mixtures?

• They are always solid.

• They can be separated by physical means.

• They are chemically bonded.

• They have fixed proportions.

Which of the following represents a molecule but NOT a compound?

• CO₂

• H₂O

• O₂

• NH₃

Which of the following is a mixture?

• Iron

• Carbon dioxide

• Saltwater

• Water

An atom is the smallest unit of a(n) (a)   .

A (a)   is formed when two or more atoms chemically combine.

A substance made of only one kind of atom is called a(n) (a)   .

(a)   can be separated into their components by physical methods.

H₂O is a chemical formula that represents a (a)   .