Atomic structure

Question 2.5. What is the relationship between

a. Energy and wavelength?

The energy of radiation is inversely proportional to its wavelength

E = hc/ λ

E = Energy of radiation

λ = wave length of any light radiation

h = Plank's constant

(b) Frequency and wavelength

Frequency is inversely related to wavelength

c = vλ

ν = c/λ

Where c = velocity of light

λ = wave length of any light radiation

ν = frequency of light radiation

Question 2.6: What species are formed by decay of neutron?

Answer. Generally neutrons are stable in most of nuclei. However, a free neutron has short half life and decays into a proton, an electron and an antineutrino.

Question 2.7: Hydrogen atom and He+ are mono electronic system, but the size of He+ is much smaller than H, why?

Answer

Size of He+ is much smaller than H, because nuclear charge of He+ is twice as greater as the nuclear charge of H atom. Although, both hydrogen and He+ ion have same valence shells with only one electron in each, but greater nuclear charge of He+ leads to greater shrinkage of its 1s orbital and hence, size of He+ is much smaller as compared to that of H atom.

Question 2.8: How the wave length of moving particles are related to momentum of electron?

Answer.

According to Einstein equation of energy

E = mc² --------- i

According to Plank's equation of energy

E = hν ---------- ii

By comparing equations i and ii, we get

mc² = hν

mc = hν/c

p = h/ c/ν

p = h / λ

p ∝ 1/λ

where p = momentum of particle

λ = wavelength of any light radiation

h = Plank's constant

Also Read : What is Heisenberg uncertainty principle?

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