When more electrons are added to a single atom, the additional electrons tend to more evenly fill in a volume of space around the nucleus so that the resulting collection ( sometimes termed the atom ’ s “ electron cloud ” ) tends toward a generally spherical zone of probability describing where the atom ’ s electrons will be found.

When a core electron is removed, leaving a vacancy, an electron from a higher energy level may fall into the vacancy, resulting in a release of energy.

When an electron in an excited molecule or atom descends to a lower energy level, it emits a photon of light equal to the energy difference.

When it emerges from the specimen, the electron beam carries information about the structure of the specimen that is magnified by the objective lens system of the microscope.

When the electron beam interacts with the specimen, it loses energy by a variety of mechanisms.

When sodium ( Na ) and chlorine ( Cl ) are combined, the sodium atoms each lose an electron, forming cations ( Na < sup >+</ sup >), and the chlorine atoms each gain an electron to form anions ( Cl < sup >−</ sup >).

When an electron absorbs energy either from light ( photons ) or heat ( phonons ), it receives that incident quantum of energy.

When an electron is excited from a lower to a higher energy level, it will not stay that way forever.

When such an electron decays without external influence, emitting a photon, that is called " spontaneous emission ".

When a light-emitting diode is forward-biased ( switched on ), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons.

When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon.

When a chlorophyll molecule at the core of the photosystem II reaction center obtains sufficient excitation energy from the adjacent antenna pigments, an electron is transferred to the primary electron-acceptor molecule, pheophytin, through a process called photoinduced charge separation.

When a positron slows down to speeds similar to those of electrons in the material, the positron will annihilate an electron, releasing two gamma photons in the process.

When an X-ray photon collides with an atom, the atom may absorb the energy of the photon and boost an electron to a higher orbital level or if the photon is very energetic, it may knock an electron from the atom altogether, causing the atom to ionize.

When ionizing radiation strikes a semiconductor, it may excite an electron out of its energy level and consequently leave a hole.

When a small bias V is applied to the system, only electronic states very near the Fermi level, within eV ( a product of electron charge and voltage, not to be confused here with electronvolt unit ), are excited.

When the temperature and pressure in the core become sufficient to ignite helium fusion, a helium flash will occur if the core is largely supported by electron degeneracy pressure ( stars under 1. 4 solar mass ).

When the primary electron beam interacts with the sample, the electrons lose energy by repeated random scattering and absorption within a teardrop-shaped volume of the specimen known as the interaction volume, which extends from less than 100 nm to around 5 µm into the surface.

When an electron absorbs energy either from light ( photons ) or heat ( phonons ), it receives that incident quanta of energy.

When an electron is excited from a lower to a higher energy level, it will not stay that way forever.

When such an electron decays without external influence, emitting a photon, that is called " spontaneous emission ".

When an atom is probed by an external mechanism, such as a photon or a beam of electrons with energies in the range of 2 keV to 50 keV, a core state electron can be removed leaving behind a hole.

When an antiproton gets close to a xenon nucleus, an electron-positron pair can be produced, and with some probability the positron will be captured by the antiproton to form antihydrogen.

When Asimov wrote his first robot stories in 1939 / 1940, the positron was a newly discovered particle and so the buzz word positronic, coined by analogy with electronic, added a contemporary gloss of popular science to the concept.

When a low-energy electron annihilates a low-energy positron ( antielectron ), they can only produce three or four gamma ray photons, since the electron and positron do not carry enough mass-energy to produce heavier particles and conservation of energy and linear momentum allow the creation of only one photon.

When an electron and a positron collide to annihilate and create gamma rays, energy is given off.

When the radioactive isotope in the ligand decays it can be measured by positron emission tomography ( PET ) or single photon emission computed tomography ( SPECT ).

When the particles are accelerated to maximum energy ( and focused to so-called bunches ), an electron and a positron bunch is made to collide with each other at one of the collision points of the detector.

When the positron was discovered by Carl David Anderson in 1932, confirming the existence of Paul Dirac's " antimatter ", it became clear that positrons could explain Chung-Yao Chao's earlier experiments, with the gamma rays being emitted from electron-positron annihilation.

When these particles collide with nucleons in the Earth's atmosphere, a shower of particles is generated, including pions.

When the molecules collide, they transfer energy to each other in varying degrees, based on how they collide.

When air molecules collide, they also bounce away from each other ( a restoring force ).

When two plates move or collide with each other, vast land areas are uplifted, forming mountains.

When these gamma rays collide with atoms in the mid-stratosphere, the gamma rays knock out electrons.

When cosmic rays enter the Earth's atmosphere they collide with molecules, mainly oxygen and nitrogen.

When particles are present in an aerosol they collide with each other.

When two Ocean current | currents collide, they create eddies.

When two continental plates collide, obduction of the oceanic crust between them is often a part of the resulting orogeny.

When the meteoroids collide with other meteoroids in the zodiacal cloud, they lose their stream association and become part of the " sporadic meteors " background.

When the two finally collide, the neutron star and red giant core will merge.

Sources close to Mayorga predict a Ricardo Mayorga vs Antonio Margarito Show down " When villains collide " the winner of the fight having one final shot at ressurecting his career and the loser retiring from boxing, a fight that will entertain fans not only in a press conference but in the ring aswell.

When continents collide, the continental crust may thicken at their edges in the collision.

When two objects collide, the program may need to do different things according to what has just hit what.

When one considers light-cone quantized superstrings, the discussion is more subtle as divergences can arise when the light-cone vertices collide.

When electrons collide with molecules of air in the gap, they excite their orbital electrons to higher energy levels.

When a particle and its antiparticle collide, their energy is converted into a force carrier particle, such as a gluon, W / Z force carrier particle, or a photon.

When in turn the energized free electrons collide with the atoms or molecules of the gas in the volume and cause ionization, if their kinetic energy is larger than the molecule or atom ionization energy.

When the pressure-gap product is high, an electron will collide with many different gas molecules as it travels from the cathode to the anode.

When two non-transparent pixels in any pair of sprites collide, the sprite collision flag is set.

When electrons of the beam impact the surface of a solid, some of them may be reflected ( as " backscattered " electrons ), and others penetrate under the surface, where they collide with the particles of the solid.