The key difference between atom and compound is that the atom is the basic unit of all matter whereas the compound is a chemical species consisting of two or more atoms.
The single elements are hardly stable under natural conditions. They form various combinations between them or with other elements in order to exist. When this happens, the properties of single elements vary and give rise to novel mixtures such as compounds.
What is Atom?
Atom is the small building block of all existing substances. They are so tiny that we cannot even observe with our naked eye. Normally atoms are in the Angstrom range. Moreover, they contain a nucleus, which has protons and neutrons. Other than that, there are other small subatomic particles in the nucleus. Also, there are electrons circling around the nucleus in an orbital.
However, most of the space in an atom is empty. The attractive forces between the positively charged nucleus (positive charge due to protons) and the negatively charged electrons maintain the atom’s shape. Atoms of the same kind have similar protons and electrons. However, the same type of atoms may differ due to the number of neutrons present, and we name them as isotopes.
Atoms can join with other atoms in various ways. Thus, they can form thousands of molecules. All elements have a diatomic or polyatomic arrangement to become stable except the Nobel gases. According to their electron donating or withdrawing abilities, they can form covalent bonds or ionic bonds. Sometimes, they have very weak attractions between atoms.
Furthermore, a series of experiments carried out by various scientists helped to determine the atom’s structure. According to the Daltons atomic theory,
- All matters are made out of atoms, and we cannot break down them further.
- All atoms of a given element are identical.
- Compounds form via the combination of two or more atoms.
- We cannot make or destroy atoms. A chemical reaction is a rearrangement of atoms.
However, there are some modifications in the Daltons theory now with the more advanced findings about the atom.
What is Compound?
A compound is a chemical substance made of two or more different chemical elements. We can name combinations of two or more of the same chemical elements as compounds. For instance, diatomic molecules like O2, H2, N2 or polyatomic molecules like P4 are not compounds; they are molecules. NaCl, H2O, HNO3, and C6H12O6 are some examples of common compounds. Therefore, compounds are a subset of molecules.
Furthermore, the elements in a compound join together by covalent bonds, ionic bonds, metallic bonds, etc. The structure of these chemical species gives the number of atoms in the compound and their ratios. In a compound, elements are present in a definite proportion. We can find these details easily by looking at a chemical formula of a compound. Moreover, they are stable, and they have a characteristic shape, colour, properties, etc.
What is the Difference Between Atom and Compound?
Atoms are much smaller than the compounds. This is because Compounds are made of two or more different types of atoms. Therefore, the key difference between atom and compound is that atoms are the basic units of all matter whereas compounds are chemical species that are consisting of two or more atoms.
Moreover, compounds have different chemical and physical properties than the atoms involved. Apart from that, another difference between atom and compound is that we cannot break down an atom further via chemical reactions, without changing the properties of it; there, we can only break down them into subatomic particles. However, we can break down a compound into molecules or atoms.
The below illustration shows the difference between atom and compound as a side by side comparison.
Summary – Atom vs Compound
Atoms are the smallest unit of all matter. Therefore, they are very small. On the other hand, compounds are combinations of atoms. The key difference between atom and compound is that the atoms are the basic units of all matter whereas the compounds are chemical species that are consisting of two or more atoms.
1. “Atom.” Wikipedia, Wikimedia Foundation, 6 Dec. 2018. Available here
2. Norman, Richard O.C., et al. “Chemical Compound.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 6 Dec. 2016. Available here