Chem 101 Section J1 2004


1. Provide the appropriate value for the missing quantum number:
n=1, l= 0, ml= _______?, ms=1/2


2. How many electrons can there be with ml = 0 when n=5?




3.Write down the complete electronic configurations for the following neutral atoms.



a)            chromium












b)            meitnerium (This is a newly discovered element of Z=109 which appears in the periodic table below iridium in group 9.)








4.†††††††† Pick the best answers for the following multiple choice questions:


i)††††††††† Hundís rule states that the lowest energy configuration for an atom is the one with

a)                  maximum number of paired electrons

b)                  lowest value of n

c)                  minimum multiplicity

d)                  maximum number of unpaired electrons




ii)                   The ability of a electron in an orbital to shield another electron from the nuclear charge is:


a)                  independent of the value of l

b)                  depends only on n

c)                  depends on ms among other things

d)†††††††† depends on l



5. Calculate the number of electrons in 1.00 mL of water at 298 K.



6. The radius of an iridium atom is 135.5 pm.How long does it take for light (in a vacuum) to traverse the distance equal to a mole of iridium atoms placed right next to each other so as to form a straight line?





7. Gallium consists of two naturally-occurring isotopes with masses of 68.926

     and 70.925 amu. The average atomic mass for gallium is 69.72 amu.


Calculate the fractional  abundance for each isotope.






8. ††††††† a) How many orbitals are there in the n = 3 level of the hydrogen atom? 



††††††††† b) Provide an/the appropriate value for the missing quantum number:


n = 6,  l = ____? , ml = -3,  ms =  Ĺ . 



c) How many electrons in the first shell of an atom with Z >1 can have the quantum number ml = 0 ? ________________



††††††††††† d) How many d-electrons are there in a Pd atom? ____________



e) A certain isotope E has a mass number equal to three times its atomic number and a neutron number that is equal to two times its atomic number. Identify isotope E.



9.†††††††† Calculate the deBroglie wavelength of a baseball with a mass of 250 g moving at 30 m/s.



10.††††††††† A street lamp emits orange light of wavelength 589.2 nm.Assuming that 60% of the electrical power consumed is converted to light at this wavelength, calculate the number of moles of photons being emitted per second if the power consumption is 500 W.