Atom Vs. Molecule
What is the difference between atom and molecule? Well, The concepts “atom” and “molecule” are part of the terminology that must be mastered;
when an introduction to Chemistry is made and for this very reason, it is important that we know the differences between atom and molecule.
Difference between Atom and Molecule
Atom
Atoms are part of the constituents of matter and range from 0.1 to 0.5 nanometers wide.
They are so small that we cannot see them through even via a common microscope.
There are many types of atoms and each has a unique number, mass, and size.
Clusters of atoms of the same type constitute the chemical elements.
An element is a pure chemical substance that has atoms of the same class and we distinguish it by its atomic number.
The atomic number derives from the number of protons present in the nucleus of the atoms of the element.
Atom vs Molecule
To date, 118 elements have been discovered and have been divided into metals, metalloids, and nonmetals.
Each element has its own set of properties and most are found on earth; while a few have developed from nuclear reactions.
All elements can be found in the periodic table, listed according to their atomic number.
The atoms of each element are composed of protons, neutrons, and electrons. Protons and neutrons are found in the nucleus, located in the center of atoms.
While the electrons that spin around, have attached to the nucleus thanks to the electromagnetic force.
The electrons have a negative electric charge and this is why they are attracted to the nucleus since the protons have a positive electric charge. On the other hand, neutrons have no electric charge.
The atoms of different elements unite and form molecules. This happens through chemical reactions.
For example, two atoms of hydrogen and one of oxygen, combine to make a molecule of water.
Molecule
A molecule is the smallest amount that can exist in a substance. It is constituted by atoms that are different from each other and for this reason, each of them can be separated.
However, such atoms cannot be separated further without provoking a nuclear reaction.
The molecules can have properties very different from those that have the elements that compose them.
For example, water behaves very differently from oxygen and hydrogen.
On the other hand, a single atom cannot exist independently in nature (without joining something).
For example, we will never find a single atom of oxygen, it is always attached to something (oxygen = O2). When molecules are formed, they can exist independently in nature; so we can always find a molecule of oxygen, carbon, or water.
The atoms of the molecules are adhered to each other in a particular way, depending on the number of bonds that the atom can make. Because of this, the molecules can have hexagonal, pentagonal forms.
Finally, molecules tend to cluster and their formation depends on their state. For example, in a gaseous state, molecules usually fly around.
In the liquid state, the molecules tend to be loosely grouped; the reason why they can move. While in the solid-state, the molecules are tighter or close together and can only vibrate.
Generally, molecules are represented in a molecular formula. For example C6H12O6 (sugar).
This molecular formula is nothing more than the name of the element, followed by the number of atoms of that element in the molecule.
Key differences between Atom and Molecule
- Atoms are constituents of matter, while molecules are made up of atoms different from each other.
- Atoms are not independently in nature, but molecules can be.
Comparison table
| Parameter | Atoms | Molecules |
| Reactivity | Mostly Reactive; Except for the noble ones. | Reactivity is less than some valence points are filled by electrons of combined elements. |
| Structure | The smallest particle with properties of an element. | forms by combining two or more atoms |
| Stability | Not always stable due to electrons. | Molecules formation takes place to attain stability. |
| Constituents | Protons, Neutrons & Electrons | Two or more atoms of the same or variable elements |
