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What are valence band?
The quantum mechanical energy band where electrons reside in semiconductors that participate in interatomic bonding.
Why are metallic compounds usually good conductors of electricity?
Metallic compounds have a delocalized structure where electrons are free to move throughout the material. These free-moving electrons can easily carry electric charge, making metallic compounds good conductors of electricity.
Do metallically bonded compounds conduct electricity?
Yes, metallic bonds conduct electricity. A characteristic of metallic bonds is that a number offree electrons are unbound in the structure. These electrons are available to support current flow. Another way to look at metallic bonds is that the bonds leave a number of electrons at energies up in the conduction band. As these electrons are already in the conduction band, any applied voltage will move them, and they'll support current flow.
Metallic bonds are formed from the sharing of valence electrons.?
false
How does the band theory of metallic bonding explain the luster of metals?
According to the band theory, any given metal atom has only a limited number of valence electrons with which to bond to all of its nearest neighbours. Extensive sharing of electrons among individual atoms is therefore required. This sharing of electrons is accomplished through the overlap of atomic orbitals of equivalent energy on the metal atoms that are immediately adjacent to one another. This overlap is delocalized throughout the entire metal sample to form extensive orbitals that span the entire solid rather than being part of individual atoms. Each of these orbitals lies at different energies because the atomic orbitals from which they were constructed were at different energies to begin with. The orbitals, equal in number to the individual atomic orbitals that have been combined, each hold two electrons, and are filled in order from the lowest to the highest energy until the number of available electrons has been used up. Groups of electrons are then said to reside in bands, which are collections of orbitals. Each band has a range of energy values that the electrons must possess to be part of that band; in some metals, there are energy gaps between bands, meaning that there are certain energies that the electrons cannot possess. The highest energy band in a metal is not filled with electrons because metals characteristically possess too few electrons to fill it. The high thermal electrical conductivities of metals is then explained by the notion that electrons may be promoted by absorption of thermal energy into these unfilled energy levels of the band.
How do atoms of metallic elements bond?
Metal atoms bond together with metallic bonds. The metallic bond has been described as a lattice of positive ions surrounded by a cloud of electrons. This simple picture is close to the truth for the alkali metals, Li, sodium etc in group 1. The more advanced model based on the above is band theory, developed by physicists and material scientists, where the free electrons are delocalised in many, what chemists would term, orbitals of very similar energy which form bands. These bands are not full and the electrons readily migrate under the influence of an electric field. Some models have been developed that are essentially MO theory. These predict a very similar view of the structure with delocalised electrons.
Electrons that are held most loosely in an atom are called what?
The electrons in the valence band, this can be 1 to 8 electrons (in the s and p orbitals of the outer shell) depending on the element.
Why are metales good electrical conductor?
the electron "gas" of unbound conduction band electrons present in all metals
What is the term valance band?
It refers to the energy levels in an atom where the electrons that participate in bonding occupy. These energy levels correspond to those of the s and p orbitals of the outermost shell of the atom being considered.
Why cant there be hole current in the conduction band?
In a semiconductor, the conduction band is filled with electrons, which are negatively charged. Holes represent the absence of electrons in the valence band, not in the conduction band. Since the conduction band is typically occupied by electrons, it cannot have holes; instead, holes exist in the valence band where electrons are missing. Therefore, while there can be free electrons in the conduction band, holes are specifically a feature of the valence band.
Why metals are good conductors of electricity give at least 4 reasons?
Metals are good conductors of electricity because :- 1.Metals they have free electrons which contribute in conduction of electricity. 2.Interms of energy bands metals they have no forbidden gape between conduction band and valence band, hence create easy overlapping of electrons from the valence band to conduction band. 3.Metals are ionizing by loosing electrons in their outermost shell so they can give out electrons, as a result of having the habit of conducting electricity because of these free electrons. 4.All metals are solid with great thermal capacity and low impurities, this feature gives all metals to be used as utensils as well as electric wires, since all metals are good conductors of heat and electricity.
What is the energy band in which free electrons exist?
Free electrons exist in the conduction band, which is the highest energy band in a material where electrons are free to move and conduct electricity.
