Notes of P-Block elements for NEET/ cbse board , Notes of P- Block elements

                                  

                                             P- Block Elements

The elements in which the differentiating electron enters into the p-orbitals of the outer most shell are called p-block elements. The elements belonging to groups IIIA IVA, VA, VIA, VIIA and zero are collectively known as p-block elements.

These elements have been placed in right hand side of the periodic table. They include metals, metalloids, non-metals and noble gases as shown below.

IIIA         IVA      VA        VIA         VIIA        Zero

ns2, np1	ns2,np2	ns2,np3	ns2,np4	ns2,np5	ns2,np6
B	C	N	O	F	Ne
Al	Si	P	S	Cl	Ar
Ga	Ge	As	Se	Br	Kr
In	Sn	Sn	Te	I	Xe
Ti	Pb	Pb	Po	At	Rn

·      General characteristics of P- block elements –

 

vElectronic Configuration-

                                    All these elements have ns² np^1-6 valence shell electronic configuration  Their s-orbitals are completely filled and p-orbitals may have 1 to 6 electrons.

 

 

 

v      Atomic and lonic Radii :

                            The atomic and ionic radii of p-block elements decrease from left to right in a given period in the periodic table. This is due to the fact that increased nuclear charge pulls the electron cloud inward.

The atomic and ionic radii of p-block elements increase in moving from top to bottom in a group. This is due to the effect of extra shells being added which over weighs the effect of incresed nuclear charge.

 

 

v      Ionisation Potential -                                                                                                                                       

                           the ionisation potentials of p-block elements increases as we move across a period from left to right and decreases on decending the group.

 

v      Electronegativity -

                           These elements have higher value of electronegativity which increases from left to right across a period and decreases on descending the group. The electronegativities of p-block elements, however, show irregular trends mainly in case of elements of groups III A and IV A.

 

 

v      Electron Affinity -                                                                      Electron affinity generally increases as we move from left to right across the period and decreases on descending a group.

 

              Nature of Compounds

 

·      p-block elements generally from covalent compounds due to large degree of polarisation of anion by cation.

 

·      Oxides - The oxides of metals are basic, that of metalloids are amphoteric and the oxides of non-metals are acidic in nature. The acidic character increases across a period while decreases on descending the

group.

 

 

·      Hydrides - The hydrides of non-metals are more stable. The stability of the hydride decreases from top to bottom in group. Thus, the order of stability of the hydrides of VA groups elements is

   NH₃, > PH3, AsH3, > SbH3, > BiH3,