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- Atom - Wikipedia
Though the word atom originally denoted a particle that cannot be cut into smaller particles, in modern scientific usage the atom is composed of various subatomic particles
- History of atomic theory - Wikipedia
The word "atom" implied indivisibility, but Dalton defined an atom as being the ultimate particle of any chemical substance, not just the elements or even matter per se
- Atom | Definition, Structure, History, Examples, Diagram, Facts . . .
An atom is the basic building block of chemistry It is the smallest unit into which matter can be divided without the release of electrically charged particles It also is the smallest unit of matter that has the characteristic properties of a chemical element
- Atom - Simple English Wikipedia, the free encyclopedia
An atom is made of three main particles: the proton, the neutron, and the electron Protons and neutrons have nearly the same size and mass (about 1 7 × 10−24 grams)
- What is an Atom? - International Atomic Energy Agency
Each atom consists of three types of particles: protons, neutrons and electrons At the centre of an atom is a dense nucleus, which contains protons and neutrons, and is much smaller than the entire atom
- atom - Wiktionary, the free dictionary
(chemistry, nuclear physics) atom, the smallest possible amount of matter which still retains its identity as a chemical element, now known to consist of a nucleus surrounded by electrons
- Atomic nucleus - Wikipedia
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford at the University of Manchester based on the 1909 Geiger–Marsden gold foil experiment
- Atom - Wikiwand
An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons The chemical elements are distinguished from each other by the number of protons that are in their atoms
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