Which of the following is an element?

What is the smallest unit of an element?

Which of these is a compound?

How many elements are found in water (H₂O)?

Which of the following is a mixture, not a compound?

What is the chemical symbol for Iron?

Which of the following is NOT a compound?

Elements combine chemically to form ______.

Which of these is a compound made of carbon and oxygen?

Which of the following is an example of a metal element?