In physics, and in particular as measured by radiometry, radiant energy is the energy of electromagnetic and gravitational radiation.[1] As energy, its SI unit is the joule (J). The quantity of radiant energy may be calculated by integratingradiant flux (or power) with respect to time. The symbol Qe is often used throughout literature to denote radiant energy ("e" for "energetic", to avoid confusion with photometric quantities). In branches of physics other than radiometry, electromagnetic energy is referred to using E or W. The term is used particularly when electromagnetic radiation is emitted by a source into the surrounding environment. This radiation may be visible or invisible to the human eye.[2][3]
https://en.wikipedia.org/wiki/Radiant_energy
Light energy
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In physics, energy is the quantitative property that must be transferred to a body or physical system to perform work on the body, or to heat it. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement in the International System of Units (SI) of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of one metre against a force of one newton.
Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field (gravitational, electric or magnetic), the elastic energy stored by stretching solid objects, the chemical energyreleased when a fuel burns, the radiant energy carried by light, and the thermal energydue to an object's temperature.
Mass and energy are closely related. Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale.
Living organisms require energy to stay alive, such as the energy humans get from food. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The processes of Earth's climate and ecosystem are driven by the radiant energy Earth receives from the Sun and the geothermal energy contained within the earth.
The total energy of a system can be subdivided and classified into potential energy, kinetic energy, or combinations of the two in various ways. Kinetic energy is determined by the movement of an object – or the composite motion of the components of an object – and potential energy reflects the potential of an object to have motion, and generally is a function of the position of an object within a field or may be stored in the field itself.
While these two categories are sufficient to describe all forms of energy, it is often convenient to refer to particular combinations of potential and kinetic energy as its own form. For example, macroscopic mechanical energy is the sum of translational and rotational kinetic and potential energy in a system neglects the kinetic energy due to temperature, and nuclear energy which combines potentials from the nuclear force and the weak force), among others.[citation needed]
| Type of energy | Description |
|---|---|
| Mechanical | the sum of macroscopic translational and rotational kinetic and potential energies |
| Electric | potential energy due to or stored in electric fields |
| Magnetic | potential energy due to or stored in magnetic fields |
| Gravitational | potential energy due to or stored in gravitational fields |
| Chemical | potential energy due to chemical bonds |
| Ionization | potential energy that binds an electron to its atom or molecule |
| Nuclear | potential energy that binds nucleons to form the atomic nucleus (and nuclear reactions) |
| Chromodynamic | potential energy that binds quarks to form hadrons |
| Elastic | potential energy due to the deformation of a material (or its container) exhibiting a restorative force as it returns to its original shape |
| Mechanical wave | kinetic and potential energy in an elastic material due to a propagated deformational wave |
| Sound wave | kinetic and potential energy in a fluid due to a sound propagated wave (a particular form of mechanical wave) |
| Radiant | potential energy stored in the fields of propagated by electromagnetic radiation, including light |
| Rest | potential energy due to an object's rest mass |
| Thermal | kinetic energy of the microscopic motion of particles, a form of disordered equivalent of mechanical energy |
https://en.wikipedia.org/wiki/Energy
In nuclear physics and particle physics, the weak interaction, which is also often called the weak force or weak nuclear force, is one of the four known fundamental interactions, with the others being electromagnetism, the strong interaction, and gravitation. It is the mechanism of interaction between subatomic particles that is responsible for the radioactive decay of atoms. The weak interaction participates in nuclear fission, and the theory describing its behaviour and effects is sometimes called quantum flavourdynamics (QFD). However, the term QFD is rarely used, because the weak force is better understood by electroweak theory (EWT).[1]
The effective range of the weak force is limited to subatomic distances, and is less than the diameter of a proton.[2]
https://en.wikipedia.org/wiki/Weak_interaction
Quantum chromodynamics binding energy (QCD binding energy), gluon binding energy or chromodynamic binding energyis the energy binding quarks together into hadrons. It is the energy of the field of the strong force, which is mediated by gluons. Motion-energy and interaction-energy contribute most of the hadron's mass.[1]
https://en.wikipedia.org/wiki/Quantum_chromodynamics_binding_energy
In physics and chemistry, ionization energy(American English spelling) or ionisation energy (British English spelling) is the minimum amount of energy required to remove the most loosely bound electron of an isolated neutral gaseous atom or molecule.[1] It is quantitatively expressed as
- X(g) + energy ⟶ X+(g) + e−
where X is any atom or molecule, X+ is the resultant ion when the original atom was stripped of a single electron, and e− is the removed electron.[2] This is generally an endothermic process. As a rule, the closer the outermost electrons are to the nucleus of the atom, the higher the atom's ionization energy.
The sciences of physics and chemistry use different units for ionization energy.[3] In physics, the unit is the amount of energy required to remove a single electron from a single atom or molecule, expressed as electronvolts. In chemistry, the unit is the amount of energy required for all of the atoms in a mole of substance to lose one electron each: molar ionization energy or approximately enthalpy, expressed as kilojoules per mole (kJ/mol) or kilocalories per mole (kcal/mol).[4]
Comparison of ionization energies of atoms in the periodic table reveals two periodic trends which follow the rules of Coulombic attraction:[5]
- Ionization energy generally increases from left to right within a given period (that is, row).
- Ionization energy generally decreases from top to bottom in a given group (that is, column).
The latter trend results from the outer electron shell being progressively farther from the nucleus, with the addition of one inner shell per row as one moves down the column.
The nth ionization energy refers to the amount of energy required to remove an electron from the species having a charge of (n-1). For example, the first three ionization energies are defined as follows:
- 1st ionization energy is the energy that enables the reaction X ⟶ X+ + e−
- 2nd ionization energy is the energy that enables the reaction X+ ⟶ X2+ + e−
- 3rd ionization energy is the energy that enables the reaction X2+ ⟶ X3+ + e−
The term ionization potential is an older and obsolete term[6] for ionization energy,[7] because the oldest method of measuring ionization energy was based on ionizing a sample and accelerating the electron removed using an electrostatic potential.
The most notable factors affecting the ionization energy include:
- Electron configuration: this accounts for most element's IE, as all of their chemical and physical characteristics can be ascertained just by determining their respective electron configuration.
- Nuclear charge: if the nuclear charge (atomic number) is greater, the electrons are held more tightly by the nucleus and hence the ionization energy will be greater.
- Number of electron shells: if the size of the atom is greater due to the presence of more shells, the electrons are held less tightly by the nucleus and the ionization energy will be lesser.
- Effective nuclear charge (Zeff): if the magnitude of electron shielding and penetration are greater, the electrons are held less tightly by the nucleus, the Zeff of the electron and the ionization energy is lesser.[8]
- Type of orbital ionized: an atom having a more stable electronic configuration has less tendency to lose electrons and consequently has higher ionization energy.
- Electron occupancy: if the highest occupied orbital is doubly occupied, then it is easier to remove an electron.
Other minor factors include:
- Relativistic effects: heavier elements (especially those whose atomic number is greater than 70) are affected by these as their electrons are approaching the speed of light, and hence have a smaller atomic radius/higher IE.
- Lanthanide and actinide contraction (and scandide contraction): the unprecedented shrinking of the elements affect the ionization energy, as the net charge of the nucleus is more strongly felt.
- Electron pair energies and exchange energy: these would only account for fully filled and half-filled orbitals. A common misconception is that "symmetry" plays a part; albeit, none so far has concluded its evidence.
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