Nitrogen Family of Elements

Introduction :

General information about the nitrogen family:
            Elements: ₇N, ₁₅P, ₃₃ As, ₅₁Sb, ₈₃ Bi
            Name: Nitrogen Family
            Electronic configuration:            ₇N = [He] 2s² 2p³
                                                               ₁₅P = [Ne] 3s² 3p³                                                                         
                                                               ₃₃As= [Ar] 3d¹⁰ 4s² 4p³
                                                                ₅₁Sb= [kr] 4d¹⁰ 5s² 5p³
                                                               ₈₃Bi = [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p³
            In this article we shall discuss about the physical properties of nitrogen family of elements 

Physical Properties of Nitrogen Family:

• Atomic radii: they are smaller than the corresponding elements of group 14 because of increase in nuclear change. Down the group they show an increase mainly due to addition of a new shell.

• Oxidation state: Because of small size, N and P can gain three electrons to complete their octets and hence show an oxidation state of -3. Because of three half-filled orbital’s, they also show an oxidation state of +3. Except N, other elements also show an oxidation state of +5 because of the presence of empty d-orbital.

• Ionization enthalpy: IEs of these elements are much higher than the corresponding elements of group14 because of increase in nuclear charge and greater stability of exactly half filled orbitals. Down the group the values decrease because of increase in atomic size.

• Metalic: Metalic character increase down the group because of decrease in ionization enthalpy and increase in atomic size. Thus N and P are non-metals. As and Sb are metalloids while Bi is a typical metal.

Occurrence:
                       Molecular nitrogen comprises 78% by quantity of the impression. It occurs as sodium nitrate, NaNO₃ and potassium nitrate. It is founded in the form of proteins in plants and animals. Phosphorus occurs in minerals of the apatite family.Ca₉(PO)₆,CaX₂(X=F,C1 or OH) Which are the main components of phosphate rock.
Electronic configuration:
                       The valence shield electronic arrangement of these fundamentals is ns²np³. The s orbital in these element is completely filled and p orbitals are half filled.
Atomic and ionic radii:
                       Covalent and ionic radii increase in size down the group. There is substantial amplify in covalent radius from N to P. Bi only small increase in covalent radius is observed.
Ionization Enthalpy:
                       Ionization Enthalpy reduces down the collection due to gradual increase in atomic size. Because of the extra stable half-filled p orbital’s electronic configuration and small size. The ionization enthalpy of the group 15 elements is much greater than that of the group 14 elements in the corresponding periods.
Electro negativity:
                     Electro negativity value in group 15 general, decreasing down the group with increasing atomic size.
Physical properties:
                     All the element of this group 15 element is polyatomic. Dinitrogen is a diatomic gas while all other are solids. Metallic quality increases downward the collection.
Chemical properties:
                     The common oxidation state of these elements is -3, +3, and +5. The tendency to exhibit -3 oxidation state decreases downs the group due to increase in size and metallic character. The stability of +5 oxidation state decrease down the group.
In the case of nitrogen, all oxidation state from +1 to +4 tent to disproportionate in acid solution. 

Some other Physical Properties of Nitrogen Family:

• Electro-negativity: These are more electronegative than group 14 elements because of further decrease in size. It decreases down the group because of increase in atomic size

• Melting points and boiling points: Melting points first increase from N to As due to increase in nuclear charge and then decrease to Sb to Bi. The decrease is due to increase in size and weakening of inter atomic forces and also due to inter pair effect resulting in the formation of 3 bonds instead of 5.

• Nature of the bonds formed: N and P mainly from covalent bonds (through them also from N^3-  and P^3-). Down the group the tendency to from covalent bonds decreases i.e. the strength of the covalent bond decreases i.e the order is N > P > As > Sb > Bi

• Density: The densities increase regularly down the group as usual.