Atom
Definition and meaning of Atom in chemistry.
An atom is the smallest unit of matter that retains the properties of an element and cannot be broken down by chemical means. Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in orbital shells.
In more detail
Atoms are the fundamental building blocks of all matter in the universe. Every element on the periodic table is defined by the number of protons in its nucleus, called the atomic number. Electrons, which carry negative charge, occupy orbitals around the nucleus, and in a neutral atom their number equals the number of protons. Atoms bond together through chemical reactions to form molecules and compounds, making them central to understanding chemistry.
Key facts
| Smallest unit of matter | that retains element properties |
|---|---|
| Main components | protons, neutrons, and electrons |
| Typical diameter | 1–3 angstroms (10⁻¹⁰ meters) |
| Field | General Chemistry |
A carbon atom (C) contains 6 protons and typically 6 neutrons in its nucleus, with 6 electrons orbiting around it. Carbon atoms are the basis of all living organisms and bond together to form diamond, graphite, and the CO2 we exhale.
Frequently asked questions
Can an atom be split?
Chemically, no, atoms are the smallest unit in chemistry. However, atoms can be split physically into subatomic particles through nuclear reactions.
Why do atoms bond?
Atoms bond to achieve lower energy states and fill their outer electron shells, creating more stable configurations as molecules and compounds.