Advertisements
Advertisements
Question
A positive ion having just one electron ejects it if a photon of wavelength 228 Å or less is absorbed by it. Identify the ion.
Solution
Given:
228 Å
Energy (E) is given by
`E = (hc)/lamda`
Here, c = Speed of light
h = Planck's constant
`E =((6.63 xx 10^-34) xx (3xx10^8))/(228xx10^-10)`
= 0.0872 × 10-16 J
As the transition takes place from n = 1 to n = 2, the excitation energy (E1) will be
`E_1 = RhcZ^2 (1/(n_1^2 )-1/n_2^2)`
`E_1 = (13.6 eV ) xx Z^2 xx (1/1^2 - 1/2^3)`
`rArr E_1 = (13.6 eV)xxZ^2xx3/4`
This excitation energy should be equal to the energy of the photon.
`therefore 13.6 xx 3/4 xx Z^2 = 0.0872xx10^-16`
`Z^2 = (0.0872xx10^-16xx4)/(13.6xx3xx1.6xx10^-19 )= 5.34`
`Z = sqrt(5.34 = 2.3`
The ion may be helium.
APPEARS IN
RELATED QUESTIONS
An electron is orbiting in 5th Bohr orbit. Calculate ionisation energy for this atom, if the ground state energy is -13.6 eV.
Calculate the radius of second Bohr orbit in hydrogen atom from the given data.
Mass of electron = 9.1 x 10-31kg
Charge on the electron = 1.6 x 10-19 C
Planck’s constant = 6.63 x 10-34 J-s.
Permittivity of free space = 8.85 x 10-12 C2/Nm2
How many electrons in an atom may have the following quantum numbers?
n = 4, `m_s = -1/2`
The ratio of kinetic energy of an electron in Bohr’s orbit to its total energy in the same orbit is
(A) – 1
(B) 2
(C) 1/2
(D) – 0.5
Which of the following parameters are the same for all hydrogen-like atoms and ions in their ground states?
A beam of light having wavelengths distributed uniformly between 450 nm to 550 nm passes through a sample of hydrogen gas. Which wavelength will have the least intensity in the transmitted beam?
Write postulates of Bohr’s Theory of hydrogen atom.
What is the energy in joules released when an electron moves from n = 2 to n = 1 level in a hydrogen atom?
For an electron in the second orbit of hydrogen, what is the moment of momentum as per the Bohr's model?
The energy of an electron in an excited hydrogen atom is - 3.4 eV. Calculate the angular momentum of the electron according to Bohr's theory. (h = 6.626 × 10-34 Js)
Using Bohr's postulates derive the expression for the radius of nth orbit of the electron.
Calculate the energy and frequency of the radiation emitted when an electron jumps from n = 3 to n = 2 in a hydrogen atom.
Why was a change in the Bohr Model of atom required? Due to which important development (s), concept of movement of an electron in an orbit was replaced by, the concept of probability of finding electron in an orbital? What is the name given to the changed model of atom?
The ratio of the ionization energy of H and Be+3 is ______.
The radius of the innermost electron orbit of a hydrogen atom is 5.3 × 10–11m. The radius of the n = 3 orbit is ______.
The ground state energy of hydrogen atoms is -13.6 eV. The photon emitted during the transition of electron from n = 3 to n = 1 unknown work function. The photoelectrons are emitted from the material with a maximum kinetic energy of 9 eV. Calculate the threshold wavelength of the material used.
Given below are two statements:
Statements I: According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increases with decrease in positive charges on the nucleus as there is no strong hold on the electron by the nucleus.
Statement II: According to Bohr's model of an atom, qualitatively the magnitude of velocity of electron increase with a decrease in principal quantum number.
In light of the above statements, choose the most appropriate answer from the options given below:
A hydrogen atom in its first excited state absorbs a photon of energy x × 10-2 eV and exited to a higher energy state where the potential energy of electron is -1.08 eV. The value of x is ______.
The energy required to remove the electron from a singly ionized Helium atom is 2.2 times the energy required to remove an electron from Helium atom. The total energy required to ionize the Helium atom completely is ______.
Write the ionisation energy value for the hydrogen atom.
