electron sea

Examples of electron sea in the following topics:

• Bonding in Metals: The Electron Sea Model

  • Metallic bonding may be described as the sharing of free electrons among a lattice of positively charged metal ions.
  • That is to say, instead of orbiting their respective metal atoms, they form a "sea" of electrons that surrounds the positively charged atomic nuclei of the interacting metal ions.
  • The electrons then move freely throughout the space between the atomic nuclei.
  • Metals are good conductors of electricity because the electrons in the electron sea are free to flow and carry electric current.
  • Positive atomic nuclei surrounded by a sea of delocalized electrons (the blue dots).

• General Properties of Metals

  • In a metal, atoms readily lose electrons to form positive ions (cations).
  • Those ions are surrounded by de-localized electrons, which are responsible for the conductivity.
  • Metals can be viewed as a collection of atoms embedded in a sea of electrons, which are highly mobile.
  • Metals are usually inclined to form cations through electron loss.
  • The "sea of electrons" is free to flow about the crystal of positive metal ions.

• Periodic Trends in Metallic Properties

  • When two elements are joined in a chemical bond, the element that attracts the shared electrons more strongly has more electronegativity.
  • The simplest conception of metals is a lattice of positive ions immersed in a "sea of electrons" that can migrate freely throughout the solid.
  • In effect, the electropositive nature of the metallic atoms allows their valence electrons to exist as a mobile fluid.
  • Because each ion is surrounded by the electron fluid in all directions, the bonding has no directional properties; this accounts for the high malleability and ductility of metals.

• Metallic Crystals

  • In a metal, atoms readily lose electrons to form positive ions (cations).
  • These ions are surrounded by delocalized electrons, which are responsible for conductivity.
  • The strength of a metal derives from the electrostatic attraction between the lattice of positive ions and the "sea" of valence electrons in which they are immersed.
  • Metallic solids are known and valued for these qualities, which derive from the non-directional nature of the attractions between the atomic nuclei and the sea of electrons.
  • Loosely bound and mobile electrons surround the positive nuclei of metal atoms.

• Conductors

  • In metallic conductors such as copper or aluminum, the movable charged particles are electrons.
  • Band theory models the behavior of electrons in solids by postulating the existence of energy bands.
  • The electrons of a single isolated atom occupy atomic orbitals, which form a discrete set of energy levels.
  • This produces a number of molecular orbitals proportional to the number of valence electrons.
  • For instance, the sea of electrons causes most metals to act both as electrical and thermal conductors.

• Extremophiles and Biofilms

  • One example of a very harsh environment is the Dead Sea, a hypersaline basin that is located between Jordan and Israel.
  • In the Dead Sea, the sodium concentration is 10 times higher than that of seawater.
  • (a) The Dead Sea is hypersaline.
  • Nevertheless, salt-tolerant bacteria thrive in this sea.
  • Deinococcus radiodurans, visualized in this false color transmission electron micrograph, is a prokaryote that can tolerate very high doses of ionizing radiation.

• The Energetics of Chemolithotrophy

  • Chemolithotrophs use electron donors oxidized in the cell, and channel electrons into respiratory chains, producing ATP.
  • An example of this is chemolithotrophic bacteria in deep sea worms or plastids, which are organelles within plant cells that may have evolved from photolithotrophic cyanobacteria-like organisms.
  • An example of this is chemolithotrophic bacteria in deep sea worms or plastids, which are organelles within plant cells that may have evolved from photolithotrophic cyanobacteria-like organisms .
  • In chemolithotrophs, the compounds - the electron donors - are oxidized in the cell, and the electrons are channeled into respiratory chains, ultimately producing ATP.
  • The electron acceptor can be oxygen (in aerobic bacteria), but a variety of other electron acceptors, organic and inorganic, are also used by various species.

• THE SEA-SERPENT

• Epsilonproteobacteria

  • A member of the class Epsilonproteobacteria occurs as an endosymbiont in the large gills of the deep water sea snail Alviniconcha hessleri.
  • Often the epsilonproteobacteria living in hydrothermal deep sea-vents exhibit chemolithotrophic features, and they are able to meet their energy needs by reducing or oxidixing chemical compounds.
  • This scanning electron microscope image shows the characteristic spiral, or corkscrew, shape of C. jejuni cells and related structures.

• Nitrate Reduction and Denitrification

  • Denitrification is a type of anaerobic respiration that uses nitrate as an electron acceptor.
  • In anaerobic respiration, denitrification utilizes nitrate (NO3-) as a terminal electron acceptor in the respiratory electron transport chain.
  • In general, it occurs where oxygen is depleted and bacteria respire nitrate as a substitute terminal electron acceptor.
  • These environments may include certain soils and groundwater, wetlands, oil reservoirs, poorly ventilated corners of the ocean, and in sea floor sediments.