what are chemical bonds and why do they form

Attraction between atoms or ions leads to a chemical bond. According to the types of bonds contained in a particle, the physical properties including melting point, hardness, electrical and thermal conductivity and solubility are curved. Chemical bonds involve alone the outermost or valence electrons of atoms. Using the archetype of the simplest element, hydrogen, its two atoms on approaching each other, statement electon-electron and proton-proton repulsions to advance separation of the atoms. But counterbalance by proton-electron attraction fuses the two hydrogen atoms forming a bond.

This archetype demonstrates the accretion, loss and sharing of electrons by atoms for possession of the selfsame figure of electrons as the dejected-blooded gas in closest proximity on the periodic table. With eight valence electrons (s2p6), all dejected-blooded gases are chemically stable in a phenomenon called the octet rule. But certain exceptions are possible. Among them, one accumulation of atoms has less than eight electrons according to hydrogen with alone one. BeH2 has aloof four valence electrons around Be, with Beryllium contributing two electrons and each hydrogen with one. The second exception applies in elements in periods 4 and above. Their atoms can accept over four surrounding valence pairs in certain compounds.

Types of Chemical Bonds

Familiarity with three types of chemical bonds is required for the SAT II Chemistry exam, ionic bonds, covalent bonds and metallic bonds.

Ionic Bonds

An electrostatic attraction between ions with adverse charges, cations and anions causes ionic bonds. They usually involve metals and nonmetals as elements active in ionic bonds are mostly from adverse ends of the periodic table with an electronegativity aberration exceeding 1.67. Being actual able, ionic bonds in compounds access melting points and booty a solid anatomy in accustomed conditions. Finally, an electron in an ionic bond is transferred from the less electronegative atom to the added electronegative element. A prime archetype of an ionic bond-content particle is NaCl or table spice.

Covalent Bonds

Atoms may share electrons instead of transferring them from atom to atom, resulting in covalent bonds. But the sharing is seldom ever equal due to the aberration in electronegativity amount of each atom. The alone exception is the bond between two atoms of the selfsame element. Covalent bonds are said to be non-polar when the aberration in electronegativity of two atoms ranges from 0 to 0.4. Polar refers to electronegativity aberration between 0.4 and 1.67. For both non-polar and polar covalent bonds, higher electronegativity in an element results in stronger attraction of the electron couple. Carbon dioxide, CO2 molecules accept two bonds which are covalent bonds.

It is possible for covalent bonds to be single, twin or triple. A single bond occurs when alone one couple of electrons is shared. This single bond is a sigma bond with the electron density being most pronounced along the line joining the two atoms.

Metallic Bonds

Metallic bonds are exclusive to metals alone, including aluminium, gold, copper and iron. Each atom in a metal shares a bond with a figure of other metal atoms, thereby allowing their electrons unrestricted movement within the metal structure. It is this specific phenomenon that is behind the properties of metals being altered, an archetype being their aerial conductivity.

That basically sums up the essence of chemical bonds, the differences in assorted types and the reasons for molecular structures being formed.

About The Author

Dr. George Grant is an experienced researcher in Bio-chemistry. He has done extensive researches and experiments in the field. He is a visiting faculty for some of the most reputed Science colleges. For added advice on Chemistry Tools and Definitions, please appointment: http://www.chemicool.com.

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Originall posted January 8, 2012