Atomic Structure

Question 1

Order of light spectrum series

Answer 1

Lyman-Blamer-paschen-Brackett-Pfund

Question 2

Order of Electromagnetic Spectrum

Answer 2

Gamma - x rays- UV- IR- microwaves- radiowaves

Question 3

Pauli exclusion principle

Answer 3

No two electrons in an atom can have the same set of quantum numbers ie an orbital cannot have more than two electrons( because spins must have opposite directions )

Question 4

Aufbau pronciple

Answer 4

Electrons are filled in the order of their increasing energies. An orbital of lower energy is filled first.

Question 5

Hunds rule

Answer 5

Pairif of elctrons doesent take place until each orbital is singly filled.

Question 6

Electronic configuration

Answer 6

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d

Question 7

Number of waves in nth orbit

Answer 7

N= 2πr/λ=n; 
Lamda = wavelength of a wave and n is principal quantum num

Question 8

Energy of electron in nth orbit

Answer 8

E(n)= -13.6 Z^/n^ ev/atom

Question 9

Wave number of spectral line

Answer 9

v(bar)= 1/λ= RZ²(1/n1^ - 1/n2^)

; R( Rydberg constant)=10^9

Question 10

Radius of nth orbit of an atom

Answer 10

r(n)= 0.529 x n^/z

Question 11

Velocity of electron in nth orbit of an atom

Answer 11

V= 2 x 10⁶ x Z/n

Question 12

Energy of a photon E= ?

Answer 12

E= hv= hc/λ=hcv(bar)=1240/λ
; h( planks constant) = 6.626 x 10^-34 Js
v= frequency of rotation
E= energy of one photon

Question 13

Relation between de Broglie wavelength and momentum of particle λ=?

Answer 13

λ= h/p=h/mv

Question 14

Photoelectric effect hv=?

Answer 14

hv= hv0 + KE
; KE is kinetic energy of emitted photoelectron 
v= frequency 
v0= threshold frequency 
h= Planks constant= 6 x 10^-34

Question 15

Heisenberg uncertainty principle Δx.Δv>= ?

Answer 15

Δx.Δv>= h/4πm

Question 16

No of subshells in nth shell ( principal quantum number n)

Answer 16

n

Question 17

Number of orbitals in nth subshell ( azimuthal quantum number l)

Answer 17

n^; l=0,1,2…(n-1)

Question 18

Number of orbitals in a sub shell ( magnetic quantum number m)

Answer 18

2l+1

; -l,-l+1,….-1,0,1,2…l-1,l

Question 19

Number of electrons in nth shell

Answer 19

2n^

Question 20

Total number of nodes N=?

Answer 20

N=n-1; n= principal quantum number

Question 21

Total number of radial nodes N=?

Answer 21

N=n-l-1; l= azimuthal quantum number and n = principal quantum number

Question 22

Orbital angular momentum of electron L= ?

Answer 22

L= √l(l+1) h/2π

; l= azimuthal quantum number and h = planks constant

Question 23

Wavelength λ increases , frequency v ?

Answer 23

decreases

Question 24

Quantum efficiency or Quantum yield =?

Answer 24

Quantum efficiency or quantum = No of molecules reacting / No of quanta absorbed

Question 25

Bohr quantisation rule mvr=?

Answer 25

mvr= n.h/2π

Question 26

Revolution per second = ?

Answer 26

Revolution per second = v/2πr= 0.657 x 10¹⁶(Z²/n³)

Question 27

Time for one revolution =?

Answer 27

Time for one revolution = 2πr/v = 1/ Revolutions per second

Question 28

Energy difference between n1 and n2 levels E(n2) - E(n1) = ?

Answer 28

E(n2) - E(n1) = 13.6Z²(1/n₁²-1/n₂²)

Question 29

Number of spectral lines for electrons de exiting from higher energy(n) level to ground state =?

Answer 29

n(n-1)/2

Question 30

Number of spectral lines when electrons de excite form a higher energy level(n2) to lower energy level(n1) =?

Answer 30

(n2-n1)(n2-n1+1)/2

Question 31

Number of spectral lines when electrons de excite form a higher energy level(n2) to lower energy level(n1) in an isolated atom =?

Answer 31

(n2-n1)

Question 32

Threshold frequency is the minim frequency required to……?

Answer 32

Threshold frequency is the minimum frequency required to eject electrons from the surface of the metal.

Question 33

De Broglie Hypothesis says that all materials possess ?

Answer 33

Both wave character as well as particle character

Question 34

Degenerate orbitals are orbitals with the same ?

Answer 34

Principal quantum number n and same sub shell

Question 35

Number of electrons in s orbital =?

Answer 35

2

Question 36

Number of electrons in p orbital =?

Answer 36

6

Question 37

Number of electrons in d orbital

Answer 37

10