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Metal

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Metal Empty Metal

Post  April Mon May 19, 2008 9:26 pm

Metal
In chemistry, a metal is defined as an element that readily loses electrons to form positive ions (cations) and forms metallic bonds between other metal atoms. (forming ionic bonds with non-metals)

Chemical properties
A chemical prpoperties is a characteristic if a pure substance that can be observe without changing it into another substance.

Physical properties
a physical properties is a characteristic of a pure substance that describes its ability to change into different substance.

Alkali metal
The alkali metals are a series of elements comprising Group 1 of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). (Hydrogen, although nominally also a member of Group 1, very rarely exhibits behavior comparable to the alkali metals). The alkali metals provide one of the best examples of group trends in properties in the periodic table, with well characterized homologous behavior down the group.

Alkaline earth metal
The alkaline earth metals are a series of elements comprising Group 2 of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). The alkaline earth metals provide a good example of group trends in properties in the periodic table, with well characterized homologous behavior down the group.”The alkaline earth metals are silvered colored, soft metals, which react readily with halogens to form ionic salts, and with water, though not as rapidly as the alkali metals, to form strongly alkaline (basic) hydroxides. For example, where sodium and potassium react with water at room temperature, magnesium reacts only with steam and calcium with hot water:

Mg + 2 H2O → Mg(OH)2 + H2


Transition metals
Because they possess the properties of metals, the transition elements are also known as the transition metals. These elements are very hard, with high melting points and boiling points. Moving from left to right across the periodic table, the five d orbitals become more filled. The d electrons are loosely bound, which contributes to the high electrical conductivity and malleability of the transition elements. The transition elements have low ionization energies. They exhibit a wide range of oxidation states or positively charged forms. The positive oxidation states allow transition elements to form many different ionic and partially ionic compounds. The formation of complexes causes the d orbitals to split into two energy sublevels, which enables many of the complexes to absorb specific frequencies of light. Thus, the complexes form characteristic colored solutions and compounds. Complexation reactions sometimes enhance the relatively low solubility of some compounds.

April

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