Rydberg constant is:
A. Same for all elements
B. Different for different elements
C. A universal constant
D. Is different for lighter elements but same for heavier elements
Answer
633.3k+ views
Hint:Generally the constant has fixed value. Rydberg constant is given by Johannes Rydberg. He gave the formula to calculate the wavelength for Balmer series. According to that the value of Rydberg constant depends upon the atomic number.
Formula used:
\[{{\text{R}}_{\text{H}}}{\text{=}}\,\dfrac{{{{\text{m}}_{\text{e}}}{{\text{e}}^{\text{4}}}}}{{{8\varepsilon }_{\text{o}}^{\text{2}}{{\text{h}}^{\text{3}}}{\text{c}}}}\]
Complete step-by-step answer:In the hydrogen spectrum, the transition from higher energy level to energy level of principle quantum number two produces the line that lies invisible. These lines are known as the Balmer series.
Johannes Rydberg gave the formula for the Balmer series of the hydrogen spectrum. The formula to determine the wavelength of transitions in hydrogen emission spectrum is as follows:
\[\dfrac{{\text{1}}}{\lambda } = \,{{\text{R}}_{\text{H}}}{{\text{Z}}^2}\left[ {\dfrac{{\text{1}}}{{{\text{n}}_{{\text{Lower}}}^{\text{2}}}} - \dfrac{{\text{1}}}{{{\text{n}}_{{\text{higher}}}^2}}} \right]\]
Where,
\[\lambda \] is the wavelength.
Z is the atomic number.
\[{{\text{R}}_{\text{H}}}\] is the Rydberg constant.
The value of Rydberg constant is as follows:
\[{{\text{R}}_{\text{H}}}\, = \,\dfrac{{{{\text{m}}_{\text{e}}}{{\text{e}}^{\text{4}}}}}{{8\varepsilon _{\text{o}}^{\text{2}}{{\text{h}}^{\text{3}}}{\text{c}}}}\]
Where,
\[{{\text{m}}_{\text{e}}}\] is the mass of electron
\[{\text{e}}\] is the change of electron
\[\varepsilon_{\text{o}}\] is the permittivity of vacuum
\[{\text{h}}\] is the Planck's constant
\[{\text{c}}\] is the speed of light
\[\dfrac{{\text{1}}}{\lambda }
=\dfrac{{{{\text{m}}_{\text{e}}}{{\text{e}}^{\text{4}}}}}{{8\varepsilon_{\text{o}}^{\text{2}}{{\text{h}}^{\text{3}}}{\text{c}}}}{{\text{Z}}^2}\left[ {\dfrac{{\text{1}}}{{{\text{n}}_{{\text{Lower}}}^{\text{2}}}} - \dfrac{{\text{1}}}{{{\text{n}}_{{\text{higher}}}^2}}} \right]\]
According to the wavelength formula of the hydrogen emission spectrum the value of Rydberg constant is directly proportional to the atomic number.
${{\text{R}}_{\text{H}}}\, \propto {{\text{Z}}^{\text{2}}}$
Every element of the periodic table has a different atomic number, so the Rydberg constant value is different for every element.
For hydrogen atom the value of Rydberg constant in per centimetre is $109678\,{\text{c}}{{\text{m}}^{ - 1}}$
So, Rydberg constant is different for different elements.
Therefore, option (B) Different for different elements is correct.
Note:Atomic number is the number of protons. Universal means the constant should have one value. Rydberg constant is not universal. Its value changes according to the atomic number. The Planck constant, Boltzmann constant or gas constant are the universal constant because these have fixed values.
Formula used:
\[{{\text{R}}_{\text{H}}}{\text{=}}\,\dfrac{{{{\text{m}}_{\text{e}}}{{\text{e}}^{\text{4}}}}}{{{8\varepsilon }_{\text{o}}^{\text{2}}{{\text{h}}^{\text{3}}}{\text{c}}}}\]
Complete step-by-step answer:In the hydrogen spectrum, the transition from higher energy level to energy level of principle quantum number two produces the line that lies invisible. These lines are known as the Balmer series.
Johannes Rydberg gave the formula for the Balmer series of the hydrogen spectrum. The formula to determine the wavelength of transitions in hydrogen emission spectrum is as follows:
\[\dfrac{{\text{1}}}{\lambda } = \,{{\text{R}}_{\text{H}}}{{\text{Z}}^2}\left[ {\dfrac{{\text{1}}}{{{\text{n}}_{{\text{Lower}}}^{\text{2}}}} - \dfrac{{\text{1}}}{{{\text{n}}_{{\text{higher}}}^2}}} \right]\]
Where,
\[\lambda \] is the wavelength.
Z is the atomic number.
\[{{\text{R}}_{\text{H}}}\] is the Rydberg constant.
The value of Rydberg constant is as follows:
\[{{\text{R}}_{\text{H}}}\, = \,\dfrac{{{{\text{m}}_{\text{e}}}{{\text{e}}^{\text{4}}}}}{{8\varepsilon _{\text{o}}^{\text{2}}{{\text{h}}^{\text{3}}}{\text{c}}}}\]
Where,
\[{{\text{m}}_{\text{e}}}\] is the mass of electron
\[{\text{e}}\] is the change of electron
\[\varepsilon_{\text{o}}\] is the permittivity of vacuum
\[{\text{h}}\] is the Planck's constant
\[{\text{c}}\] is the speed of light
\[\dfrac{{\text{1}}}{\lambda }
=\dfrac{{{{\text{m}}_{\text{e}}}{{\text{e}}^{\text{4}}}}}{{8\varepsilon_{\text{o}}^{\text{2}}{{\text{h}}^{\text{3}}}{\text{c}}}}{{\text{Z}}^2}\left[ {\dfrac{{\text{1}}}{{{\text{n}}_{{\text{Lower}}}^{\text{2}}}} - \dfrac{{\text{1}}}{{{\text{n}}_{{\text{higher}}}^2}}} \right]\]
According to the wavelength formula of the hydrogen emission spectrum the value of Rydberg constant is directly proportional to the atomic number.
${{\text{R}}_{\text{H}}}\, \propto {{\text{Z}}^{\text{2}}}$
Every element of the periodic table has a different atomic number, so the Rydberg constant value is different for every element.
For hydrogen atom the value of Rydberg constant in per centimetre is $109678\,{\text{c}}{{\text{m}}^{ - 1}}$
So, Rydberg constant is different for different elements.
Therefore, option (B) Different for different elements is correct.
Note:Atomic number is the number of protons. Universal means the constant should have one value. Rydberg constant is not universal. Its value changes according to the atomic number. The Planck constant, Boltzmann constant or gas constant are the universal constant because these have fixed values.
Recently Updated Pages
Write structures of the following compounds i 2 Chloro3methylpentane class 11 chemistry CBSE

What is BLO What is the full form of BLO class 8 social science CBSE

Explain the Treaty of Vienna of 1815 class 10 social science CBSE

A Paragraph on Pollution in about 100-150 Words

XIX+XXX A 49 B 51 C 55 D 44 class 5 maths CBSE

If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

Trending doubts
One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Find the value of the expression given below sin 30circ class 11 maths CBSE

What do you mean by retardation What is its SI uni class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

10 examples of friction in our daily life

Difference between physical and chemical change class 11 chemistry CBSE

