Chemistry Class 11 NCERT Solutions: Chapter 2 Structure of Atom Part 2

Q: 3. How many neutrons and protons are there in the following nuclei?

Equation

Answer:

Equation

Atomic mass = 13

Atomic number = Number of protons = 6

Number of neutrons = (Atomic mass) -(Atomic number)

Equation

Equation

Atomic mass = 16

Atomic number = 8

Number of protons = 8

Number of neutrons = (Atomic mass) Equation (Atomic number)

Equation

Equation

Atomic mass = 24

Atomic number = Number of protons = 12

Number of neutrons = (Atomic mass) Equation (Atomic number)

Equation 12 = 12

Equation

Atomic mass = 56

Atomic number = Number of protons = 26

Number of neutrons = (Atomic mass) Equation (Atomic number)

Equation 26 = 30

Equation

Atomic mass = 88

Atomic number = Number of protons = 38

Number of neutrons = (Atomic mass) - (Atomic number)

Equation

Q: 4. Write the complete symbol for the atom with the given atomic number (Z) and Atomic mass (A)

(i) Equation

(ii) Equation

(iii) Equation

Answer:

(i) Equation

Equation Equation

(iii) Equation

Q: 5 Yellow light emitted from a sodium lamp has a wavelength Equation Calculate the frequency and wave number Equation of the yellow light.

Answer:

From the expression,

Equation

We get,

Equation

Where,

Equation

Wavelength of yellow light Equation

Substituting the values in expression (i):

Equation

Thus, frequency of yellow light emitted from the sodium lamp

Equation

Wave number of yellow light, Equation

Equation

Explore Solutions for Chemistry