Atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy vol. 1 (1808)
Electric field of a positive and a negative point charge
The Geiger–Marsden experiment:
Left: Expected results: alpha particles passing through the plum pudding model of the atom with negligible deflection.
Right: Observed results: a small portion of the particles were deflected by the concentrated positive charge of the nucleus.
Diagram showing field lines and equipotentials around an electron, a negatively charged particle. In an electrically neutral atom, the number of electrons is equal to the number of protons (which are positively charged), resulting in a net zero overall charge
The Bohr model of the atom, with an electron making instantaneous "quantum leaps" from one orbit to another with gain or loss of energy. This model of electrons in orbits is obsolete.
Coulomb's torsion balance
The binding energy needed for a nucleon to escape the nucleus, for various isotopes
A potential well, showing, according to classical mechanics, the minimum energy V(x) needed to reach each position x. Classically, a particle with energy E is constrained to a range of positions between x1 and x2.
3D views of some hydrogen-like atomic orbitals showing probability density and phase (g orbitals and higher are not shown)
This diagram shows the half-life (T½) of various isotopes with Z protons and N neutrons.
These electron's energy levels (not to scale) are sufficient for ground states of atoms up to cadmium (5s2 4d10) inclusively. Do not forget that even the top of the diagram is lower than an unbound electron state.
An example of absorption lines in a spectrum
Graphic illustrating the formation of a Bose–Einstein condensate
Scanning tunneling microscope image showing the individual atoms making up this gold (100) surface. The surface atoms deviate from the bulk crystal structure and arrange in columns several atoms wide with pits between them (See surface reconstruction).
Periodic table showing the origin of each element. Elements from carbon up to sulfur may be made in small stars by the alpha process. Elements beyond iron are made in large stars with slow neutron capture (s-process). Elements heavier than iron may be made in neutron star mergers or supernovae after the r-process.

In ordinary matter, negative charge is carried by electrons, and positive charge is carried by the protons in the nuclei of atoms.

- Electric charge

The protons have a positive electric charge, the electrons have a negative electric charge, and the neutrons have no electric charge.

- Atom
Atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy vol. 1 (1808)

12 related topics

Alpha

Hydrogen atomic orbitals at different energy levels. The more opaque areas are where one is most likely to find an electron at any given time.

Electron

Hydrogen atomic orbitals at different energy levels. The more opaque areas are where one is most likely to find an electron at any given time.
A beam of electrons deflected in a circle by a magnetic field
J. J. Thomson
Robert Millikan
The Bohr model of the atom, showing states of an electron with energy quantized by the number n. An electron dropping to a lower orbit emits a photon equal to the energy difference between the orbits.
In quantum mechanics, the behavior of an electron in an atom is described by an orbital, which is a probability distribution rather than an orbit. In the figure, the shading indicates the relative probability to "find" the electron, having the energy corresponding to the given quantum numbers, at that point.
Standard Model of elementary particles. The electron (symbol e) is on the left.
Example of an antisymmetric wave function for a quantum state of two identical fermions in a 1-dimensional box. If the particles swap position, the wave function inverts its sign.
A schematic depiction of virtual electron–positron pairs appearing at random near an electron (at lower left)
A particle with charge q (at left) is moving with velocity v through a magnetic field B that is oriented toward the viewer. For an electron, q is negative so it follows a curved trajectory toward the top.
Here, Bremsstrahlung is produced by an electron e deflected by the electric field of an atomic nucleus. The energy change E2 − E1 determines the frequency f of the emitted photon.
Probability densities for the first few hydrogen atom orbitals, seen in cross-section. The energy level of a bound electron determines the orbital it occupies, and the color reflects the probability of finding the electron at a given position.
A lightning discharge consists primarily of a flow of electrons. The electric potential needed for lightning can be generated by a triboelectric effect.
Lorentz factor as a function of velocity. It starts at value 1 and goes to infinity as v approaches c.
Pair production of an electron and positron, caused by the close approach of a photon with an atomic nucleus. The lightning symbol represents an exchange of a virtual photon, thus an electric force acts. The angle between the particles is very small.
An extended air shower generated by an energetic cosmic ray striking the Earth's atmosphere
Aurorae are mostly caused by energetic electrons precipitating into the atmosphere.
During a NASA wind tunnel test, a model of the Space Shuttle is targeted by a beam of electrons, simulating the effect of ionizing gases during re-entry.

The electron is a subatomic particle (denoted by the symbol or or ) whose electric charge is negative one elementary charge.

The Coulomb force interaction between the positive protons within atomic nuclei and the negative electrons without, allows the composition of the two known as atoms.

The quark content of the neutron. The color assignment of individual quarks is arbitrary, but all three colors must be present. Forces between quarks are mediated by gluons.

Neutron

Subatomic particle, symbol or, which has a neutral charge, and a mass slightly greater than that of a proton.

Subatomic particle, symbol or, which has a neutral charge, and a mass slightly greater than that of a proton.

The quark content of the neutron. The color assignment of individual quarks is arbitrary, but all three colors must be present. Forces between quarks are mediated by gluons.
Nuclear fission caused by absorption of a neutron by uranium-235. The heavy nuclide fragments into lighter components and additional neutrons.
Models depicting the nucleus and electron energy levels in hydrogen, helium, lithium, and neon atoms. In reality, the diameter of the nucleus is about 100,000 times smaller than the diameter of the atom.
A schematic of the nucleus of an atom indicating radiation, the emission of a fast electron from the nucleus (the accompanying antineutrino is omitted). In the Rutherford model for the nucleus, red spheres were protons with positive charge and blue spheres were protons tightly bound to an electron with no net charge. 
The inset shows beta decay of a free neutron as it is understood today; an electron and antineutrino are created in this process.
The Feynman diagram for beta decay of a neutron into a proton, electron, and electron antineutrino via an intermediate heavy W boson
The leading-order Feynman diagram for decay of a proton into a neutron, positron, and electron neutrino via an intermediate boson.
Institut Laue–Langevin (ILL) in Grenoble, France – a major neutron research facility.
Cold neutron source providing neutrons at about the temperature of liquid hydrogen
The fusion reaction rate increases rapidly with temperature until it maximizes and then gradually drops off. The D–T rate peaks at a lower temperature (about 70 keV, or 800 million kelvins) and at a higher value than other reactions commonly considered for fusion energy.
Transmutation flow in light water reactor, which is a thermal-spectrum reactor

Protons and neutrons constitute the nuclei of atoms.

The common means of detecting a charged particle by looking for a track of ionization (such as in a cloud chamber) does not work for neutrons directly.

The quark content of a proton. The color assignment of individual quarks is arbitrary, but all three colors must be present. Forces between quarks are mediated by gluons.

Proton

The quark content of a proton. The color assignment of individual quarks is arbitrary, but all three colors must be present. Forces between quarks are mediated by gluons.
Ernest Rutherford at the first Solvay Conference, 1911
Proton detected in an isopropanol cloud chamber
Protium, the most common isotope of hydrogen, consists of one proton and one electron (it has no neutrons). The term "hydrogen ion" implies that that H-atom has lost its one electron, causing only a proton to remain. Thus, in chemistry, the terms "proton" and "hydrogen ion" (for the protium isotope) are used synonymously

A proton is a stable subatomic particle, symbol, H+, or 1H+ with a positive electric charge of +1e elementary charge.

One or more protons are present in the nucleus of every atom.

Photons are emitted by a cyan laser beam outside, orange laser beam inside calcite and its fluorescence

Photon

Elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force.

Elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force.

Photons are emitted by a cyan laser beam outside, orange laser beam inside calcite and its fluorescence
Photoelectric effect: the emission of electrons from a metal plate caused by light quanta – photons.
The cone shows possible values of wave 4-vector of a photon. The "time" axis gives the angular frequency (rad⋅s−1) and the "space" axis represents the angular wavenumber (rad⋅m−1). Green and indigo represent left and right polarization
Thomas Young's double-slit experiment in 1801 showed that light can act as a wave, helping to invalidate early particle theories of light.
In 1900, Maxwell's theoretical model of light as oscillating electric and magnetic fields seemed complete. However, several observations could not be explained by any wave model of electromagnetic radiation, leading to the idea that light-energy was packaged into quanta described by . Later experiments showed that these light-quanta also carry momentum and, thus, can be considered particles: The photon concept was born, leading to a deeper understanding of the electric and magnetic fields themselves.
Up to 1923, most physicists were reluctant to accept that light itself was quantized. Instead, they tried to explain photon behaviour by quantizing only matter, as in the Bohr model of the hydrogen atom (shown here). Even though these semiclassical models were only a first approximation, they were accurate for simple systems and they led to quantum mechanics.
Photons in a Mach–Zehnder interferometer exhibit wave-like interference and particle-like detection at single-photon detectors.
Stimulated emission (in which photons "clone" themselves) was predicted by Einstein in his kinetic analysis, and led to the development of the laser. Einstein's derivation inspired further developments in the quantum treatment of light, which led to the statistical interpretation of quantum mechanics.
Different electromagnetic modes (such as those depicted here) can be treated as independent simple harmonic oscillators. A photon corresponds to a unit of energy E = hν in its electromagnetic mode.

The intrinsic properties of particles, such as charge, mass, and spin, are determined by gauge symmetry.

During a molecular, atomic or nuclear transition to a lower energy level, photons of various energy will be emitted, ranging from radio waves to gamma rays.

A composite particle proton is made of two up quark and one down quark, which are elementary particles

Subatomic particle

A composite particle proton is made of two up quark and one down quark, which are elementary particles
The Standard Model classification of particles

In physical sciences, a subatomic particle is a particle that composes an atom.

It is also certain that any particle with an electric charge is massive.

Wave functions of the electron in a hydrogen atom at different energy levels. Quantum mechanics cannot predict the exact location of a particle in space, only the probability of finding it at different locations. The brighter areas represent a higher probability of finding the electron.

Quantum mechanics

Wave functions of the electron in a hydrogen atom at different energy levels. Quantum mechanics cannot predict the exact location of a particle in space, only the probability of finding it at different locations. The brighter areas represent a higher probability of finding the electron.
Fig. 1
Position space probability density of a Gaussian wave packet moving in one dimension in free space.
1-dimensional potential energy box (or infinite potential well)
Some trajectories of a harmonic oscillator (i.e. a ball attached to a spring) in classical mechanics (A-B) and quantum mechanics (C-H). In quantum mechanics, the position of the ball is represented by a wave (called the wave function), with the real part shown in blue and the imaginary part shown in red. Some of the trajectories (such as C, D, E, and F) are standing waves (or "stationary states"). Each standing-wave frequency is proportional to a possible energy level of the oscillator. This "energy quantization" does not occur in classical physics, where the oscillator can have any energy.
Schematic of a Mach–Zehnder interferometer.
Max Planck is considered the father of the quantum theory.
The 1927 Solvay Conference in Brussels was the fifth world physics conference.

Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles.

For example, the stability of bulk matter (consisting of atoms and molecules which would quickly collapse under electric forces alone), the rigidity of solids, and the mechanical, thermal, chemical, optical and magnetic properties of matter are all results of the interaction of electric charges under the rules of quantum mechanics.

Deuterium

One of two stable isotopes of hydrogen (the other being protium, or hydrogen-1).

One of two stable isotopes of hydrogen (the other being protium, or hydrogen-1).

Deuterium discharge tube
Ionized deuterium in a fusor reactor giving off its characteristic pinkish-red glow
Emission spectrum of an ultraviolet deuterium arc lamp
Harold Urey, deuterium's discoverer
The "Sausage" device casing of the Ivy Mike H bomb, attached to instrumentation and cryogenic equipment. The 20-ft-tall bomb held a cryogenic Dewar flask with room for 160 kg of liquid deuterium.

The nucleus of a deuterium atom, called a deuteron, contains one proton and one neutron, whereas the far more common protium has no neutrons in the nucleus.

While the order of magnitude is reasonable, since the deuterium radius is of order of 1 femtometer (see below) and its electric charge is e, the above model does not suffice for its computation.

Hydrogen atom (center) contains a single proton and a single electron. Removal of the electron gives a cation (left), whereas the addition of an electron gives an anion (right). The hydrogen anion, with its loosely held two-electron cloud, has a larger radius than the neutral atom, which in turn is much larger than the bare proton of the cation. Hydrogen forms the only charge-+1 cation that has no electrons, but even cations that (unlike hydrogen) retain one or more electrons are still smaller than the neutral atoms or molecules from which they are derived.

Ion

Hydrogen atom (center) contains a single proton and a single electron. Removal of the electron gives a cation (left), whereas the addition of an electron gives an anion (right). The hydrogen anion, with its loosely held two-electron cloud, has a larger radius than the neutral atom, which in turn is much larger than the bare proton of the cation. Hydrogen forms the only charge-+1 cation that has no electrons, but even cations that (unlike hydrogen) retain one or more electrons are still smaller than the neutral atoms or molecules from which they are derived.
Schematic of an ion chamber, showing drift of ions. Electrons drift faster than positive ions due to their much smaller mass.
Avalanche effect between two electrodes. The original ionization event liberates one electron, and each subsequent collision liberates a further electron, so two electrons emerge from each collision: the ionizing electron and the liberated electron.
Equivalent notations for an iron atom (Fe) that lost two electrons, referred to as ferrous.
Mixed Roman numerals and charge notations for the uranyl ion. The oxidation state of the metal is shown as superscripted Roman numerals, whereas the charge of the entire complex is shown by the angle symbol together with the magnitude and sign of the net charge.
An electrostatic potential map of the nitrate ion . The 3-dimensional shell represents a single arbitrary isopotential.

An ion is an atom or molecule with a net electrical charge.

Aurora at Alaska showing light created by charged particles and magnetism, fundamental concepts to electromagnetism study

Electromagnetism

Aurora at Alaska showing light created by charged particles and magnetism, fundamental concepts to electromagnetism study
Hans Christian Ørsted
André-Marie Ampère
James Clerk Maxwell
Representation of the electric field vector of a wave of circularly polarized electromagnetic radiation.
Magnetic reconnection in the solar plasma gives rise to solar flares, a complex magnetohydrodynamical phenomenon.

Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.

The electromagnetic attraction between atomic nuclei and their orbital electrons holds atoms together.

Hydrogen's purple glow in its plasma state, the most abundant in the universe

Matter

Any substance that has mass and takes up space by having volume.

Any substance that has mass and takes up space by having volume.

Hydrogen's purple glow in its plasma state, the most abundant in the universe
Under the "quarks and leptons" definition, the elementary and composite particles made of the quarks (in purple) and leptons (in green) would be matter—while the gauge bosons (in red) would not be matter. However, interaction energy inherent to composite particles (for example, gluons involved in neutrons and protons) contribute to the mass of ordinary matter.
Quark structure of a proton: 2 up quarks and 1 down quark.
A comparison between the white dwarf IK Pegasi B (center), its A-class companion IK Pegasi A (left) and the Sun (right). This white dwarf has a surface temperature of 35,500 K.
Phase diagram for a typical substance at a fixed volume. Vertical axis is Pressure, horizontal axis is Temperature. The green line marks the freezing point (above the green line is solid, below it is liquid) and the blue line the boiling point (above it is liquid and below it is gas). So, for example, at higher T, a higher P is necessary to maintain the substance in liquid phase. At the triple point the three phases; liquid, gas and solid; can coexist. Above the critical point there is no detectable difference between the phases. The dotted line shows the anomalous behavior of water: ice melts at constant temperature with increasing pressure.
Galaxy rotation curve for the Milky Way. Vertical axis is speed of rotation about the galactic center. Horizontal axis is distance from the galactic center. The sun is marked with a yellow ball. The observed curve of speed of rotation is blue. The predicted curve based upon stellar mass and gas in the Milky Way is red. The difference is due to dark matter or perhaps a modification of the law of gravity. Scatter in observations is indicated roughly by gray bars.

All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles (or combination of particles) that act as if they have both rest mass and volume.

They carry an electric charge of −1⁄3 e (down-type quarks) or +2⁄3 e (up-type quarks).