Question of Exercise 2

Atomic Structure of Class 11

If the speed of electron in the Bohr’s first orbit of hydrogen atom be x, then the speed of the electron in third Bohr orbit is


Option 1

Option 2

Option 3 3x

Option 4 9x

Frequently Asked Questions

The charge on a proton is

A: -1.602×10-19C

B: 1.602×10-19C

C: 0

D: None of the above





Protons are the positively charged particles that make up a hydrogen atom's nucleus. A proton has a mass of 1.6726219×10-27 kilograms.

A proton's mass is the same as that of a hydrogen atom. One electron and one proton make up a hydrogen atom. Because the mass of an electron is deemed unimportant, the mass of a hydrogen atom can be said to be equal to the mass of a proton. A proton has a mass of 1840 times that of an electron.

A proton's charge is the same as and opposite that of an electron. As a result, it has a single positive charge having the value 1.602×10-19C.

Final answer:

Option B is the correct answer, The charge on a proton is 1.602×10-19C.



The hybridisation of Ni inNi(CO)4 is








  • The outer electronic configuration of Ni is 3d84s2 .
  • Now ,Ni is in zero oxidation state. The 2 electrons from 4s orbitals moves to the 3d orbital and we get completely filled 3d orbital and vacant 4s and 4 p orbital. 


  • This way we get sp3  hybridization and shape is tetrahedral.
  • It does not have any unpaired electrons so it is diamagnetic in nature.

Final Answer:-

The hybridization of Ni in Ni(CO)4   complex  is  (C ) sp3



Express the following in the scientific notation

(i) 0.0048 (ii) 234,000 (iii) 8008 (iv) 500.0 (v) 6.0012




  • In scientific notation the number is represented as 

represented 1

  • The scientific notations will be:

represented 2

Final Answer:-

  • The Scientific notations are

represented 2

The cell in which the following reaction occurs

2Fe3+  (aq) + 2I- (aq) → 2Fe3+ (aq) + I2 (s) has Ecell  = 0.236 V at 298 K.

Calculate the standard Gibbs energy and the equilibrium constant of the cell reaction.




Eº= 0.236 V

T = 293  k

We know that G =- nFEº

F = 96500

n = 2 (no. of electron)

ΔG = -2965000.236 = -45.548kJ

From nernst equation

Ecell = Eº- 0.591/n logk

Ecell = 0 (at equilibrium) 

Logk =  nEº/0.591= 2×0.236/0.591

Logk = 7.98

K = 107.98= 9.616 ×107

Final Answer:

Hence standard Gibbs energy = -45.548kJ & equilibrium constant of the cell reaction K = 9.616 107.



The SI unit of weight is

A: kilogram

B: gram

C: newton

D: milligram




substance's mass can be defined as a measurement of its physical 3D structure and quantity.

A substance's mass is usually expressed in kilograms or grams. The kilograme is a metric unit of mass used by the International System of Units. 'kg' is another way of writing it.

Final Answer :

Thus, option A is the correct answer. A(Kilogram)


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