A report on Atom

Atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy vol. 1 (1808)
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.
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 This model of electrons in orbits is obsolete.
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.

Smallest unit of ordinary matter that forms a chemical element.

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

115 related topics with Alpha

Overall

Effective nuclear charge

0 links

Actual amount of positive charge experienced by an electron in a multi-electron atom.

Actual amount of positive charge experienced by an electron in a multi-electron atom.

The effective atomic number Zeff, (sometimes referred to as the effective nuclear charge) of an atom is the number of protons that an electron in the element effectively 'sees' due to screening by inner-shell electrons.

Snowflakes are a very well-known example, where subtle differences in crystal growth conditions result in different geometries.

Crystallization

1 links

Snowflakes are a very well-known example, where subtle differences in crystal growth conditions result in different geometries.
Crystallized honey
Low-temperature SEM magnification series for a snow crystal. The crystals are captured, stored, and sputter-coated with platinum at cryo-temperatures for imaging.
Crystal growth
Crystallization of sodium acetate.
Solubility of the system Na2SO4 – H2O
Vertical cooling crystallizer in a beet sugar factory
DTB Crystallizer
Schematic of DTB

Crystallization or crystallisation is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal.

An example of spectroscopy: a prism analyses white light by dispersing it into its component colors.

Spectroscopy

4 links

General field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation.

General field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation.

An example of spectroscopy: a prism analyses white light by dispersing it into its component colors.
A huge diffraction grating at the heart of the ultra-precise ESPRESSO spectrograph.
UVES is a high-resolution spectrograph on the Very Large Telescope.

Spectroscopy is used in physical and analytical chemistry because atoms and molecules have unique spectra.

Visual representation of alpha decay

Alpha decay

5 links

Type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.

Type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.

Visual representation of alpha decay

Alpha decay is by far the most common form of cluster decay, where the parent atom ejects a defined daughter collection of nucleons, leaving another defined product behind.

Crystal structure of table salt (sodium in purple, chloride in green)

Crystal structure

2 links

Crystal structure of table salt (sodium in purple, chloride in green)
Planes with different Miller indices in cubic crystals
Dense crystallographic planes
The hcp lattice (left) and the fcc lattice (right)
Quartz is one of the several crystalline forms of silica, SiO2. The most important forms of silica include: α-quartz, β-quartz, tridymite, cristobalite, coesite, and stishovite.
Simple cubic (P)
Body-centered cubic (I)
Face-centered cubic (F)

In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material.

Jean Perrin in 1926

Avogadro constant

2 links

Jean Perrin in 1926
Josef Loschmidt

The Avogadro constant (NA or L ) is the proportionality factor that relates the number of constituent particles (usually molecules, atoms or ions) in a sample with the amount of substance in that sample.

The Standard Model of elementary particles, with the gauge bosons in the fourth column in red

Gauge boson

3 links

Bosonic elementary particle that acts as the force carrier for elementary fermions.

Bosonic elementary particle that acts as the force carrier for elementary fermions.

The Standard Model of elementary particles, with the gauge bosons in the fourth column in red

Gauge bosons are different from the other kinds of bosons: first, fundamental scalar bosons (the Higgs boson); second, mesons, which are composite bosons, made of quarks; third, larger composite, non-force-carrying bosons, such as certain atoms.

Timeline of the metric expansion of space, where space, including hypothetical non-observable portions of the universe, is represented at each time by the circular sections. On the left, the dramatic expansion occurs in the inflationary epoch; and at the center, the expansion accelerates (artist's concept; not to scale).

Big Bang

7 links

Initial state of high density and temperature.

Initial state of high density and temperature.

Timeline of the metric expansion of space, where space, including hypothetical non-observable portions of the universe, is represented at each time by the circular sections. On the left, the dramatic expansion occurs in the inflationary epoch; and at the center, the expansion accelerates (artist's concept; not to scale).
Panoramic view of the entire near-infrared sky reveals the distribution of galaxies beyond the Milky Way. Galaxies are color-coded by redshift.
Artist's depiction of the WMAP satellite gathering data to help scientists understand the Big Bang
Abell 2744 galaxy cluster – Hubble Frontier Fields view.
The cosmic microwave background spectrum measured by the FIRAS instrument on the COBE satellite is the most-precisely measured blackbody spectrum in nature. The data points and error bars on this graph are obscured by the theoretical curve.
9 year WMAP image of the cosmic microwave background radiation (2012). The radiation is isotropic to roughly one part in 100,000.
Focal plane of BICEP2 telescope under a microscope - used to search for polarization in the CMB.
Chart shows the proportion of different components of the universe – about 95% is dark matter and dark energy.
The overall geometry of the universe is determined by whether the Omega cosmological parameter is less than, equal to or greater than 1. Shown from top to bottom are a closed universe with positive curvature, a hyperbolic universe with negative curvature and a flat universe with zero curvature.

After its initial expansion, an event that is by itself often called "the Big Bang", the universe cooled sufficiently to allow the formation of subatomic particles, and later atoms.

Methane, CH4; is among the simplest organic compounds.

Organic compound

5 links

In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds.

In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds.

Methane, CH4; is among the simplest organic compounds.
The L -isoleucine molecule, C6H13NO2, showing features typical of organic compounds. Carbon atoms are in black, hydrogens gray, oxygens red, and nitrogen blue.

Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known.

Combinations of three u, d or s quarks forming baryons with a spin-3⁄2 form the uds baryon decuplet

Baryon

9 links

Type of composite subatomic particle which contains an odd number of valence quarks .

Type of composite subatomic particle which contains an odd number of valence quarks .

Combinations of three u, d or s quarks forming baryons with a spin-3⁄2 form the uds baryon decuplet
Combinations of three u, d or s quarks forming baryons with a spin-1⁄2 form the uds baryon octet

These particles make up most of the mass of the visible matter in the universe and compose the nucleus of every atom.