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what do you mean by bond in atoms? what are the types of it?

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what do you mean by bond in atoms? what are the types of it?

Postby subham » Thu Feb 27, 2014 7:08 pm

Bond:- The Arrangement of atoms in a material determines the behaviour and properties of that material. In exists matter are in three states-solid, gas, liquid.

The atoms and molecules in a solid state are more closely as compared to gaseous and liquid states and are held together be strong mutual forces of attraction. These interatomic forces are electrostatic in nature and depend upon the electronic structure of matter. These forces arise because of differences in the electron clouds of atoms. In other words, the valence electron, or those in the outer shell, of atoms determine their attraction for their neighbours. When physical attraction between molecules or atoms of a material is great, the material is held tightly together. Molecules in solids are bound tightly together. When the attractions are weaker substance may be in liquid form and free to flow. Gases exhibit virtually no attractive forces between atoms or molecules, and their particles are free to move independently or each other.

Why Atoms bond together – We use a concept called “Happy Atoms”. We figure that most atoms want to be happy, just like you. The idea behind Happy Atoms is that atomic shell like to be full.

Example if you are an atom and you have shell, you want your shell to be full.

Some atoms have too many electrons (one or two extra). These atoms like to give up their electrons. Some atoms are really close to having a full shell. Those atoms go around looking for other atoms who want to give up an electron.

We should start with the atoms that have atomic numbers between 1 and 18. There is a 2-8-8 rule for these elements. The first shell is filled with 2 electrons, the second is filled with 8 electrons, and the third is filled with 8. We know that sodium (Na) have 1 and Chlorine (Cl) have a 7 of extra electrons. They, like all atoms, want to be happy. They have two possibilities: they can try to get to eight electrons to fill up their third shell, or they can give up a few electrons and have a filled second shell

NA(2,8,1) Cl(2,8,7)

Sodium need 7 for fill complete shell and chlorine need only one. . It is always easier to give away one or two electrons than it is to go out and find six or seven to fill your shells.so sodium give 1 electron to chlorine, then both made complete shell structure.

Image

Following type of bond in atom

1. Ionic Bond- Ionic bond are mainly formed in inorganic compound like NaCl and KOH etc and never in pure element. In this type of bond , one or more electrons are wholly transferred from an atom of one element to the atom of the other and the element are held together by the force of attraction duo to the opposite polarity of the charge. Elements are classified as either electropositive or electronegative depending upon when they tend to lose or gain electrons in order to achieve this stable outer shell electron configuration

Characteristics of ionic bond:-

1. Ionic bonds are unidirectional.
2. They are generally crystalline in nature
3. The are rigid+
4. They have high melting and boiling point because strong electrostatic forces bind them.
5. They are generally non-conductors of electricity but their metals and solutions conduct electricity.
6. They are usually highly soluble in water and other polar solvents but insoluble in organic solvents
2. COVALENT BOND- it is formed by sharing electrons rather than by transfer of electrons. .Electrons are shared when an atom need electrons to complete its outer shell and can share those electrons with its neighbour. The electrons are then part of both atoms and both shells are filled.


Characteristics of covalent bond:-

1. Covalent bonds are directional in nature.
2. They can be solids,liquids and gases.
3. They are soft and have low melting and boiling points.
4. They are generally insulaters electricity.
5. They are soluble in non polar solvents such as benzene and carbon tetrachloride and insoluble in water.
3. Metallic bond – in this type of bond, the atoms do not share or exchange electrons to bond together. Instead many electrons are more or less free to move throughout the metal, so that each electron can interact with many of the fixed atoms.

Characteristics of metallic bond:-

1. Metallic bond are crystalline in nature.
2. They are good conductors of electricity.
3. They are high thermal conductivity
4. They are high reflectivity and lustre
5. They have usually moderate to high, melting temperature

Answered by Sunil
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subham
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