Last Updated on February 15, 2024.

Molecules are the general term used to describe atoms connected by a chemical bond.

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So all combinations of atoms are molecules. Compounds are molecules made up of atoms from all sorts of different elements.

1. Every combination of atoms is a molecule.

Question 1 of 2

2. Hydrogen gas (H2) is a molecule, but not a compound because it is made of only one element.

Question 2 of 2


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Video Transcription

So all compounds are actually molecules, but beware, not every molecule is a compound.

For example, Hydrogen gas (formula: H2) is actually a molecule. However, it is not a compound as H2 is made up of just one element.

Water (H2O), on the other hand, may be called both a molecule and a compound as it is made up of oxygen (O) and hydrogen (H) atoms.

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You can write every molecule as a list of all the atoms that form them.

For example, we write NaCl as a way to represent table salt (the molecular formula) that formed through an ionic bond between chlorine (Cl) and sodium (Na).

A molecular formula may also be used for a covalent molecule like water (H2O).

In case we see more than just one atom of any particular element within one single molecule, we are using a subscript number at the right side of the symbol for the atom to indicate the number of atoms of that specific element present in every molecule.

Once again:

Molecules are atoms that are connected by chemical bonds.

So we can also say that all combinations of atoms are what we call molecules.

When we speak about compounds, we refer to molecules that consist of atoms from a number of different elements.

So we can say that all compounds are molecules, but not all molecules are compounds.

When we have a single molecule that has more than just 1 atom of a particular element, we use a subscript number to the right of the symbol for that atom to show the number of atoms of the element present in a molecule.