CONTRIBUTION OF PROTONS, NEUTRONS TO ATOMIC NECLEUS IN TERMS OF PROTON NUMBER AN NUCLEUS NUMBER:ISOTOPES, Hydrogen, Carbon

 

CONTRIBUTION OF PROTONS, NEUTRONS TO ATOMIC NECLEUS IN TERMS OF PROTON NUMBER AN NUCLEUS NUMBER:

 

            Each element has fixed number of proton in its nucleus. It is the characteristic feature of an element. No two elements can have same number of protons. During chemical reaction ions are formed and even in ions number of protons remains fixed only electron number is changed. Number of protons in the nucleus of an atom is called proton number or atomic number. In the periodic table elements are arranged in order of their increasing atomic number.

 

            Nucleus number or atomic mass of an atom is the since of no of protons and no of nucleus present in the nucleus of an atom. Number of neutrons may be different  in different atoms of the same element due to the pressure of isotopes but even in isotopes number of protons are same.

 

ISOTOPES:

 

            Atoms of the same element which have same atomic number (z) but different mass number (A) are called isotopes of the element. Isotopes have different mass number because they have different number of neutrons in their nucleus. Isotopes have the same chemical properties  due to similarly Ƶ but slightly different physical properties are due to different A.

 

                        CL   P = 17, E = 17, N = 18

 

                        CL   P = 17, E = 17, N = 20

 

Hydrogen

           

                        H       P = 1, E = 1, N = 0

 

                        H       P = 1, E = 1, N = 1

                        H       P = 1, E = 1, N = 2     

 

Carbon

                        C          P = 6, E = 6, N = 6

C          P = 6, E = 6, N = 7

 

 

ENERGY LEVEL:

 

            Electrons moved around the nucleus in definite energy levels which are called shells. Each shell is identified by a number which is called principle quantum number and is represented by n. The value of n are 1,2,3,4,5,6, and 7. Each value of N correspond to the number of shell or the number of period in the periodic table. Shell is further divided into Subshell with same principal quantum number but having different energy levels. The shell may have subshell like s, p, d or f. The increasing order of energy in sub shells is from s to f i.e. s subshell  has least energy level than gradually it increases from p, d upto f sublevel. S < p < d < f. The number of subshells related to different quantum number are given below.

 

NUMBER OF SHELL	PRINCIPAL QUANTUM NUMBER (N)	NUMBER OF SUBSHELL	TYPE OF SUBSHELL
1st Shell	1	One	1s.
2nd Shell	2	Two	2s, 2p
3rd Shell	3	Three	3s, 3p, 3d
4th Shell	4	Four	4s, 4p, 4d, 4f
5th Shell	5	Five	5s, 5p, 5d, 5f
6th Shell	6	Six	6s, 6p, 6d,  6f
7th Shell	7	Seven	7s, 7p, 7d, 7f

 

            A region or volume of space within which there is a high probability of finding an electron is called an orbital. Each type of subshell have different number of degenerate orbits i.e. orbitals of equal energy.  A s subshell consists of s orbital only. A p subshell consists of three p orbitals. A d subshell consists of five d orbitals and a f subshell consists of seven degenerate orbitals. Each orbital can hold maximum of two electrons therefore, s subshell have maximum capacity of two electrons, p subshell can have six electrons, d subshell can have ten electrons and f subshell can have maximum fourteen electron capacity.

 

TYPE OF SUBSHELL	NUMBER OF ORBITALS	NUMBER OF MAXIMUM ELECTRONS
s	One	2
p	Three	6
d	Five	10
f	Seven	14