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 This model of electrons in orbits is obsolete.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

Interference fringes, showing fine structure (splitting) of a cooled deuterium source, viewed through a Fabry–Pérot interferometer.

Fine structure

1 links

Interference fringes, showing fine structure (splitting) of a cooled deuterium source, viewed through a Fabry–Pérot interferometer.
800x800px
Relativistic corrections (Dirac) to the energy levels of a hydrogen atom from Bohr's model. The fine structure correction predicts that the Lyman-alpha line (emitted in a transition from n=2 to n=1) must split into a doublet.

In atomic physics, the fine structure describes the splitting of the spectral lines of atoms due to electron spin and relativistic corrections to the non-relativistic Schrödinger equation.

Absorptions bands in the Earth's atmosphere created by greenhouse gases and the resulting effects on transmitted radiation.

Absorption band

0 links

Absorptions bands in the Earth's atmosphere created by greenhouse gases and the resulting effects on transmitted radiation.
Schematic diagram of electromagnetic absorption
A Mössbauer absorption spectrum of 57Fe with very sharp lines

According to quantum mechanics, atoms and molecules can only hold certain defined quantities of energy, or exist in specific states.

An electron in a Bohr model atom, moving from quantum level n=3 to n=2 and releasing a photon.

Atomic electron transition

1 links

An electron in a Bohr model atom, moving from quantum level n=3 to n=2 and releasing a photon.

Atomic electron transition is a change (or jump) of an electron from one energy level to another within an atom or artificial atom.

A simplified representation of a helium atom, having an estimated (calculated) diameter of 62 picometres

Picometre

0 links

Unit of length in the metric system, equal to 1 m, or one trillionth (1⁄1,000,000,000,000) of a metre, which is the SI base unit of length.

Unit of length in the metric system, equal to 1 m, or one trillionth (1⁄1,000,000,000,000) of a metre, which is the SI base unit of length.

A simplified representation of a helium atom, having an estimated (calculated) diameter of 62 picometres

Atoms are between 62 and 520 pm in diameter, and the typical length of a carbon–carbon single bond is 154 pm.

The atomic orbital wavefunctions of a hydrogen atom. The principal quantum number (n) is at the right of each row and the azimuthal quantum number (ℓ) is denoted by letter at top of each column.

Azimuthal quantum number

2 links

Quantum number for an atomic orbital that determines its orbital angular momentum and describes the shape of the orbital.

Quantum number for an atomic orbital that determines its orbital angular momentum and describes the shape of the orbital.

The atomic orbital wavefunctions of a hydrogen atom. The principal quantum number (n) is at the right of each row and the azimuthal quantum number (ℓ) is denoted by letter at top of each column.
Illustration of quantum mechanical orbital angular momentum.
"Vector cones" of total angular momentum J (purple), orbital L (blue), and spin S (green). The cones arise due to quantum uncertainty between measuring angular momentum components (see vector model of the atom).

Connected with the energy states of the atom's electrons are four quantum numbers: n, ℓ, mℓ, and ms. These specify the complete, unique quantum state of a single electron in an atom, and make up its wavefunction or orbital.

Position of the transactinide elements in the periodic table.

Transuranium element

3 links

Atomic number of uranium.

Atomic number of uranium.

Position of the transactinide elements in the periodic table.

107. bohrium, Bh, named after the Danish physicist Niels Bohr, important in the elucidation of the structure of the atom (1981). This discovery was also claimed by the JINR. IUPAC concluded that the GSI had been the first to convincingly synthesise the element. The GSI team had originally proposed nielsbohrium (Ns) to resolve the naming dispute on element 105, but this was changed by IUPAC as there was no precedent for using a scientist's first name in an element name.

A sample of lead solidified from the molten state

Lead

3 links

Chemical element with the symbol Pb and atomic number 82.

Chemical element with the symbol Pb and atomic number 82.

A sample of lead solidified from the molten state
The Holsinger meteorite, the largest piece of the Canyon Diablo meteorite. Uranium–lead dating and lead–lead dating on this meteorite allowed refinement of the age of the Earth to 4.55 billion ± 70 million years.
Flame test: lead colors flame pale blue
Lead(II) oxide
Lead and oxygen in a tetragonal unit cell of lead(II,IV) oxide
Chart of the final part of the s-process, from mercury to polonium. Red lines and circles represent neutron captures; blue arrows represent beta decays; the green arrow represents an alpha decay; cyan arrows represent electron captures.
Lead is a fairly common element in the Earth's crust for its high atomic number (82). Most elements of atomic number greater than 40 are less abundant.
World lead production peaking in the Roman period and the Industrial Revolution.
Ancient Greek lead sling bullets with a winged thunderbolt molded on one side and the inscription "ΔΕΞΑΙ" ("take that" or "catch") on the other side.
Roman lead pipes
Elizabeth I of England was commonly depicted with a whitened face. Lead in face whiteners is thought to have contributed to her death.
16px
Lead mining in the upper Mississippi River region in the United States in 1865
Promotional poster for Dutch Boy lead paint, United States, 1912
Primary production of lead since 1840
Bricks of lead (alloyed with 4% antimony) are used as radiation shielding.
A 17th-century gold-coated lead sculpture
Lead glass
Lead yellow and red lead
Symptoms of lead poisoning
Kymographic recording of the effect of lead acetate on frog heart experimental set up.
Battery collection site in Dakar, Senegal, where at least 18 children died of lead poisoning in 2008
Radiography of a swan found dead in Condé-sur-l'Escaut (northern France), highlighting lead shot. There are hundreds of lead pellets; a dozen is enough to kill an adult swan within a few days. Such bodies are sources of environmental contamination by lead.

A lead atom has 82 electrons, arranged in an electron configuration of [Xe]4f145d106s26p2.

Periodic Table organized by atomic orbitals.

Core electron

1 links

Periodic Table organized by atomic orbitals.
Gold Spectrum
620x620px

Core electrons are the electrons in an atom that are not valence electrons and do not participate in chemical bonding.

Germicidal lamps are simple low-pressure mercury vapor discharges in a fused quartz envelope.

Gas-discharge lamp

2 links

Electric discharge through an ionized gas, a plasma.

Electric discharge through an ionized gas, a plasma.

Germicidal lamps are simple low-pressure mercury vapor discharges in a fused quartz envelope.
Jules Verne's "Ruhmkorff lamp"
A compact fluorescent lamp
15 kW xenon short-arc lamp used in IMAX projectors

In operation, some of the electrons are forced to leave the atoms of the gas near the anode by the electric field applied between the two electrodes, leaving these atoms positively ionized.

The unit cell of rutile. Ti(IV) centers are grey; oxygen centers are red. Notice that oxygen forms three bonds to titanium and titanium forms six bonds to oxygen.

Oxide

2 links

The unit cell of rutile. Ti(IV) centers are grey; oxygen centers are red. Notice that oxygen forms three bonds to titanium and titanium forms six bonds to oxygen.
Oxides, such as iron(III) oxide or rust, which consists of hydrated iron(III) oxides Fe2O3·nH2O and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)3), form when oxygen combines with other elements
Carbon dioxide is the main product of fossil fuel combustion.
Carbon monoxide is the product of the incomplete combustion of carbon-based fuels and a precursor to many useful chemicals.
Nitrogen dioxide is a problematic pollutant from internal combustion engines.
Sulfur dioxide, the principal oxide of sulfur, is emitted from volcanoes.
Nitrous oxide ("laughing gas") is a potent greenhouse gas produced by soil bacteria.

An oxide is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula.