Bonding in solids

Every atoms are held together in said by interatomic force. These forces actong between the atom are electrostatic in nature. The process of holding atom together in a crystal is known as bonding.
Types of bonding in solids on the basis of electron distribution or forces.

1.ionic bond:- These bond are formed in crystal in which electron are transferred from one atom to another atom. Such that the crystal is made up of positive ion or negative ion. It is non-directional in nature. Its bonding energy is of order of 5ev to 10ev.
Example:- Nacl, CaO etc.
Properties of ionic bonds
1. They have higher enthalpies of fusion and vaporization than molecular compounds.
2.They are hard.
3.They are brittle.
4.They have high melting points and also high boiling points.
5.They conduct electricity but only when they are dissolved in water.

2. Covalent bond:- These bond in crystal are formed by sharing of electron equally between neighbouring atom. It is directional in nature. Its crystal are brittle and hard. It is less strong than ionic bond. Example:-chlorine, diamond etc.
Properties of covalent bond
1.-Low boiling points and melting points.
2. Various colors.
3. Poor conductors of heat and electricity.
4.Brittle solids.

3. Metallic bond:- In crystal with these bond. The valence electrons of constituent atom free to move through out the crystal. They do not form the permanent bond Example:- copper,silvar etc.
Properties of metallic bond.
1.Malleability.
2.Ductility.
3.High melting and boiling point.
4.High electrical and thermal conductivity.
5.Metallic lustre.

4. Vandar waal bond:- In this bond crystal arises due to dipolar force between atom of the crystal. its a weak binding. With low melting and boiling point.
Example:- Argon, neon etc.
Properties of Vandar waal bond.
1. These bonds are weak force of attraction.
2. Low melting and boiling point.
3. Low electrical and thermal conductivity.
4.  This bond break easily.
5. Metallic lustre

5.Hydrogen bond:- The hydrogen bond is formed between an atom of hydrogen and extremely electronegtive atom.Example:- fluorine, oxygen, nitrogen etc. It is essentially ionic in chracter. Example:- Hydrogen water and ice.
Properties of hydrogen bond.
Solubility: Lower alcohols are soluble in water because of the hydrogen bonding which can take place between water and alcohol molecule.
Volatility: As the compounds involving hydrogen bonding between different molecules have a higher boiling point, so they are less volatile.
Viscosity and surface tension: The substances which contain hydrogen bonding exists as an associated molecule. So their flow becomes comparatively difficult. They have higher viscosity and high surface tension.
The lower density of ice than water: In the case of solid ice, the hydrogen bonding gives rise to a cage-like structure of water molecules. As a matter of fact, each water molecule is linked tetrahedral to four water molecules. The molecules are not as closely packed as they are in a liquid state. When ice melts, this case like structure collapses and the molecules come closer to each other. Thus for the same mass of water, the volume decreases and density increases. Therefore, ice has a lower density than water at 273 K. That is why ice floats.

HYDROGEN BONDING

Crytal structure 

It is description of ordered arrangement of atom, ions & molecules in a crystalline material.

State of matter
There are 5 states of matter in the world
1. Solid
2. Liquid
3. Gas
4. Plasma
5. Base-Einstein condensate

In 1924. Albert Einstein & Satyandra nath base predicted this BEC & it was refered as the 5th state of matter. BEC is a state of matter of a dilute gas of  bosons cooled to temperature very close to absolute to zero.
2.Liquid:- It is a nearly compressible fluid that confirms to the shape of its container but retains a constant volume independent of pressure. It is the only state with a defined volume but no fixed shape.
3. Gas:- It is a substance of matter in a state in which it will expand freely to fill the wall of container having no fixed shape a pure gas may be made up of individual atom. Example- noble gas like neon. Elemental molecules mase from one type of atom. Example:- oxygen. Or compound molecules made from a variety of atom Example:- carbon dioxide.
4. Plasma:- Plasma is a hot ionized gas consisting of approximately equal no. of positively charge ion & negative charged electron. It is considered as the 4th state of matter because the characteristics of plasma  are significance different from those of ordinary neutral gas.

Crytal structure

Types of solids

1. Crystalline solid
2. Amorphous solid
1. Crystalline solid:- The solid in which the constituent  particle of  matter are arrangement and organized  in a specific manner. These solids contain crystal in their structure and each crystal has definite geometry. All most solids fall in the category of crystalline solid having metallic elements (sulphur and iodine). Example:- sugar, mica, diamond etc.
NOTE:- Crystalline solids are low energy states and amorphous solids are high energy state.

2. Amorphous solid:- The solid in which the constituent particle of matter are arrange in a different manner. It is a non-crystalline solid with no proper arrangement of atom in a solid lattice. One of the most common example of amorphous solids is glass, which is used widely in the manufacturing sector.
Example:- plastic,glass,rubber etc.
Amorphous solids are isotrophic and it is due to the properties will be independent of the direction in which they are measured.

Difference between Crystalline solid and Amorphous solid

Crystalline solid:- 1. The solid in which the constituent  particle of  matter are arrangement and organized  in a specific manner.
2. It melts at fixed temperature.
3. The arrangement of constituent particle is regular.
4. Crystalline solid are regular and definite shape.
5. When cut, two smooth & plain piece are obtained.
6. Definite heat of fusion.
7. They are true solids.
8. They are anisotropic
9. They possess symmetry and interfacial angles.
10.  Example:- sugar, mica, diamond etc.

Amorphous solid 1. The solid in which the constituent particle of matter are arrange in a different manner.
2.It melts steadily over range of temperature.
3. The arrangement of constituent particle is irregular.
4. Amorphous solid are irregular shape in nature.
5. When cut two surface irregular shape is obtained.
6. Indefinite heat of fusion.
7. They are pesudo solid.
8. They are isotropic.
9. They do not possess symmetry and interfacial angles.
10. Example:- plastic,glass,rubber etc.

Prokaryotic cell

Prokaryotic cell:- Prokaryotic cell is that cell which lacks a well-defined nucleus and membrane-bound organelles.

For example: Bacteria,cyanobacteria,PPLO [Pleuro-pheumonia like organism]

Prokaryotic cell diagram

1. Cell wall: cell wall in bacteria is made up of peptido-glycan which is a polymer of NAG & NAM.
NAG:- N-acetylglucosamine  : NAM:- N-acethylmuramic acid
· It provide shape and rigidity to cell
2. Glycocalyx:- It is made up of polysccaride orprotein or both.
Function-  It helps in the attachment of bacterial cell of various surfaces. In some bacteria,it also contribute to pathogenicity.[ Disease causing ability]
3. Flagella:- It is present in some bacteria. It is a locomotory structure that helps in the movement of bacteria. It is made up of protein called flagellin. Flagella is single standed in bacteria.

4. Plasma membrane: Plasma membrane is selectively permeable membrane present around cell
5. Mesosome: The are invagination or infolding of plasma membrane.

It has a role in DNA replication
It has a role in the formation cell septum for cell division. 
Also help in repiration, secretion process and to increase the surface area of plasma membrane
6. Nucleoid: The naked DNA of prokaryotes which is not enclosed inside the nucleus is called nucleoid/ Genophore. In addition to genomic DNA, many bacteria have small circular DNA outside genomic DNA plasmids, which confers traits like antibiotic-resistance to bacteria.
7. Ribosomes: They are the protein factory of the cell. In prokaryotes ribosome lie freely in the cytoplasm and are of 70`S type, which have two subunits 50S & 30S.There are two types of ribosomes 
1.70S ribosomes
2. 80S ribosomes
8. Thylakoid: They are present in some bacteria & blue-green algae which are autotrophic.They lie in cytoplasm and contain pigmets such as bacteria chlorophyll.
9. Protein granules & lipid globules: They lie freely in the cytoplasm.
10. Gas vacuoles: they are not true vacuoles & are present in some bacteria to provide buoyancy. 
Example:- These gas are present in purple & green photosynthetic bacteria.

Genitcs of blood group

1. The ÁBÒ blood group system is controlled by three alleles Ia,Ib&i. Ia encodes for A antigen. Blood group shows multiple allelism.

2.Ib encodes for B antigen & 'i' does not encodes for any antigen.

3.Ia&Ib arw co-dominant& each is dominant over 'i'.

4. The antigen encoded are parent on surface of RBCs

5. Over 300 blood group specificities on red cells have been identified, many of which are polymorphic. The molecular mechanisms responsible for these polymorphisms are diverse, though many simply represent single nucleotide polymorphisms (SNPs). Other mechanisms include the following: gene deletion; single nucleotide deletion and sequence duplication, which introduce reading-frame shifts; nonsense mutation; intergenic recombination between closely linked genes, giving rise to hybrid genes and hybrid proteins; and a SNP in the promoter region of a blood group gene. Examples of these various genetic mechanisms are taken from the ABO, Rh, Kell, and Duffy blood group systems. Null phenotypes, in which no antigens of a blood group system are expressed, are not generally polymorphic, but provide good examples of the effect of inactivating mutations on blood group expression. As natural human ‘knock-outs’, null phenotypes provide useful clues to the functions of blood group antigens. Knowledge of the molecular backgrounds of blood group polymorphisms provides a means to predict blood group phenotypes from genomic DNA. This has two main applications in transfusion medicine: determination of foetal blood groups to assess whether the foetus is at risk from haemolytic disease and ascertainment of blood group phenotypes in multiply transfused, transfusion-dependent patients, where serological tests are precluded by the presence of donor red cells. Other applications are being developed for the future.
6.Rh Blood group system:-If the individual possess rhesus antigen, he is Rh+ & if rhesus antigen is absent, he is Rh-

Univesal donor:-That individual that does not have any antigen on its RBC. Ex O-

Universal acceptor:- That possess all the antigen on RBC.Ex AB+ ( A antigen, Bantigen,Rhesus antigen)