Nucleus
Definition and meaning of Nucleus in chemistry.
The nucleus is the dense, positively charged core at the center of an atom, composed of protons and neutrons.
In more detail
The nucleus contains virtually all of an atom's mass despite occupying only a tiny fraction of its volume, making atoms largely empty space. The number of protons in the nucleus defines the atomic number and determines the element's identity. Neutrons, which carry no electrical charge, contribute to an atom's mass and stability. Electrons are attracted to the nucleus by electromagnetic forces and occupy orbitals around it, but they are not part of the nucleus itself. The nuclear composition directly influences an atom's properties and how it bonds with other atoms. Ernest Rutherford discovered the nucleus in 1911 through his gold-foil experiment, which revealed the atom has a concentrated, positively charged center.
Key facts
| Field | General Chemistry |
|---|---|
| Composition | Protons and neutrons |
| Size | Approximately 1-10 femtometers (10^-15 meters) in diameter |
| Discovery | Ernest Rutherford, 1911 |
A carbon-12 nucleus contains 6 protons and 6 neutrons (12 nucleons total), making it the most abundant stable isotope of carbon.
Frequently asked questions
How do electrons relate to the nucleus?
Electrons are negatively charged particles attracted to the nucleus by electromagnetic force and occupy orbitals around it, but they are not contained within the nucleus itself.
What is the difference between protons and neutrons?
Protons carry a positive charge and determine the element's atomic number, while neutrons carry no electrical charge. Both particles contribute significantly to an atom's mass.