Elements, Compounds & Counting Atoms

Front

What does the subscript in a chemical formula tell you?

Back

It tells you how many atoms of an element are present in a molecule.

Front

Which of the following is a molecule of a compound? H2, Cl2, H2O, F2

Back

H2O is a molecule of a compound.

Front

How many atoms does an element have if no subscript is shown?

Back

1 atom.

Front

How many elements are in the chemical formula HCl?

Back

2 elements.

Front

What is a compound?

Back

A compound is a substance formed when two or more elements chemically bond together.

Front

What is the difference between an element and a compound?

Back

An element is a pure substance made of only one type of atom, while a compound is made of two or more different types of atoms.

Front

What does the formula H2O represent?

Back

It represents water, which is a compound made of 2 hydrogen atoms and 1 oxygen atom.

Front

What is the significance of the number in front of a chemical formula, like 2 in 2H2O?

Back

It indicates the number of molecules present.

Front

What is the chemical formula for table salt?

Back

NaCl, which is a compound made of sodium and chlorine.

Front

What is an atom?

Back

An atom is the smallest unit of an element that retains the properties of that element.