Posted by **qwer** on Monday, April 25, 2011 at 9:12am.

A monochromatic light beam with energy 204eV is used to excite the Be+3 (H –like atom with Z=4) from its ground state to some excited state m. Neglect the finite nuclear mass correction.

a) Find the quantum number m of this excited state.

b) Following this transition the excited Be+3 atom emits a spectral line at 30.42nm as a result of the transition from this excited state m to some other lower state n. Find the quantum number of this new state.

c) Calculate the orbital radius of the electron in the state n.

- physics -
**drwls**, Monday, April 25, 2011 at 9:58am
(a) For BeIII with Z=4, use the Rydberg equation for the energy levels. They will be 4^2 = 16 times more widely separated than for hydrogen.

E(m) = 13.58 eV*16/n^2 = 217.3 /m^2 eV

For a transition from the ground state (m=1),

204 eV = 217.3/1 - 217.3/m^2

217.3/m^2 = 16.4

m = 4 (probably) There may be some accuracy issues with the value of the Rydberg that I used.

(b) Convert the wavelength to photon energy in eV. Then use the Rydberg equation to compute n.

E = h*c/(wavelength) = ____ eV

E = 204 eV - R/n^2 = 204 - 217.3/n^2

Solve for n

(c) Bohr orbit radius = ao * n^2/Z

where ao is the hydrogen ground state Bohr radius

## Answer This Question

## Related Questions

- Physics - A hydrogen atom in an excited state emits a Balmer beta photon ...
- Chemistry - The first excited state of the hydrogen atom is separated from the ...
- Chemistry - An electron is excited from the n=1 ground state to the n=3 state in...
- Physics - A hydrogen atom is in the ground state. It absorbs energy and makes a ...
- Atomic physics - 5)a. Electrons accelerated by a potential difference of 12.23 V...
- physics - A hydrogen atom in an excited state emits a Balmer beta photon ...
- physics - A singly ionized helium atom is in the ground state. It absorbs energy...
- physics - In Bohr's model of the hydrogen atom, the radius of an orbit a. is ...
- chemistry - The following describes the process of an atom emitting light. Place...
- physics - The higher the energy level occupied by an electron in the hydrogen ...

More Related Questions