Matter units {atom, matter}| are small and have chemical properties. Atoms have same properties as larger amounts of same element.
types
Most atoms are metals. There are 22 non-metal elemental solids, liquids, and gases.
number
Nature has 90 atoms, and particle accelerators can make more than 13 heavy atoms.
mass
Hydrogen atom has mass 10^-24 grams. Heaviest atom is 250 times more massive.
size
Atoms are 99.99% empty space. Atoms have diameter 10^-8 centimeters. Largest-atom volume is 10 times hydrogen-atom volume.
parts: nucleus
Atoms have positively charged protons and neutral neutrons in orbits at central atom nucleus. Number of protons determines atom properties. Nuclei have diameter 10^-12 centimeters. Protons and neutrons have diameter 10^-13 centimeter.
parts: electrons
Electrons rapidly orbit nucleus at varying distances. Electron mass is 10^-27 grams. In neutral atom, protons equal electrons.
energy
Average kinetic energy equals binding energy. If electromagnetic force is same as now, too-small atoms fly apart, because electron velocities are greater. Too-large atoms cannot exist, because electron velocities are too slow to stay in orbit.
magnetism
Atoms have magnetism, because charges move at relativistic speeds. Most atoms have symmetrical electron and proton arrangements, so magnetic effects cancel. Atoms can have odd numbers of protons and/or neutrons and have net magnetism.
large elements
Carbon nucleus can form from three helium nuclei. Elements higher than carbon can form, because carbon atoms have resonance energy at which three helium nuclei are stable and can add more protons and neutrons.
model
Atom models can have infinite number of linear vibrators, which represent all atom frequencies, momenta, and positions.
Physical Sciences>Physics>Matter>Atom
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Date Modified: 2022.0224