Question

what are quantum numbers​

Answer 1

$\huge{\boxed{\purple{Quantum\;Numbers}}}$

Definition

• Quantum numbers are intoduced by group of scientists to know the postion on electron in an orbit of an atom

These quantum numbers are of four types

1. Principle Quantum number
2. Azimuthal Quantum number
3. Magnetic Quantum number
4. Spin Quantum number

$\large{\boxed{\green{Principle\;Quantum\;number}}}$

• It is proposed by Neil's Bohr
• It is denoted by "n"
• It signifies the size and energy of the orbit
• It has numbers from n = 1,2,3,......
• Maximum number of electrons in a shell can be given by,$2{n}^{2}$
• In a Bohr orbit , the angular momentum of an electron in its ${n}^{th}$ is given by,
• $mvr\;=\dfrac{nh}{2\pi}$

$\large{\boxed{\green{Azimuthal\;Quantum\;number}}}$

• It is proposed by Sommerfield
• It is denoted by "l"
• The value of l can be given by, they depend on values on n
• l = 0,1,2,......(n-1)
• It indicates the shape of the orbital

$\large{\boxed{\green{Magnetic\;Quantum\;number}}}$

• It is proposed by Lande
• It is denoted by "m"
• It indicates the sub-sub energy levels of the orbital
• The values of of m depends on "l".
• The values of m are from -l to +l
• The total values of m are given by , m = 2l+1
• The number of electrons in s,p,d and f orbital are 1, 3, 5, 7

$\large{\boxed{\green{Spin\;Quantum\;number}}}$

• It is proposed by Goudsmith and Uhlenbeck
• It is denoted by "s"
• It is independent of other quantum numbers
• The values of s are :-
• $\dfrac{1}{2}\;and\;\dfrac{-1}{2}$

• If the electron revolves in anti clockwise then the spin is represented by $\dfrac{-1}{2}$
• If the electron revolves in clockwise then the spin is represented by $\dfrac{1}{2}$
• The maximum number of electrons in an orbital = 2

Answer 2

Answer:

There are 4 types of quantum numbers

1st quantum numbers- principal quantum number

2nd quantum number- angular or azimuthal quantum number

3rd quantum number

4th quantum number- spin quantum number

Explanation:

1st quantum number gives energy of elections. It represents shells or orbits (K,L,M.....). It gives distance of an electron from nucleus.

Denoted by- n, n=1,2,3,4....

2nd quantum number gives momentum of electron. It represents subshells (s,p,d,f)

Denoted by- l (small L) l=0,1,2,3.....

3rd quantum number gives energy states in subshells. There are (2l+1) values of m ranging from -l to +l

denoted by m

s subshell has 1 energy state

p subshell has 3 energy states

d subshell has 5 energy states

f subshell has 7 energy states

4th quantum number gives spin of electron. Electrons can have either CW or ACW spin. Hence spin number is +1/2 for CW and -1/2 for ACW

and there are 2(n×n) electrons in a subshell where n is the principal quantum number.