The energy of any one-electron species in its nth state (n = principal quantum number) is given by E = –BZ2 /n2 where Z is the charge on the nucleus and B is 18 2.180 10  J. a) Find the ionization energy of the Be3+ ion in its first excited state in kilojoules per mole. b) Find the wavelength of light given off from the Be3+ ion by electrons dropping from the fourth (n = 4) to the second (n = 2) energy levels.

Explanation:

(a) The given data is as follows.

            B =

            Z = 4 for Be

Now, for the first excited state = 2; and if it is ionized.

Therefore, ionization energy will be calculated as follows.

         I.E =

              =

Converting this energy into kJ/mol as follows.

           = 5249 kJ/mol

Therefore, the ionization energy of the ion in its first excited state in kilojoules per mole is 5249 kJ/mol.

(b) Change in ionization energy is as follows.

                     =

or,                 =

Therefore, wavelength of light given off from the ion by electrons dropping from the fourth (n = 4) to the second (n = 2) energy levels .

a pan containing water is placed in a positio n where it is exposed to a 10 mile per hour wind. the pan contains a uniform depth of 1.27 cm of water, is quite wide, and has a length of 2.44 m in the wind direction. the water in the pan is at a constant temperature of 15.5 °c.