CHEM 120 Electrons in Atoms and the Periodic Table - Full Solutions

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1. What is the wavelength, in nanometers, of light with an energy content of 2.63E(-6) kJ/mol?
Answer: 4.55E4 nm


2. What is the maximum kinetic energy of an ejected electron if platinum metal is irradiated with 167-nm light? The threshold wavelength for a platinum metal surface is 212 nm.
Answer: 2.52E-19 J


3. What is the frequency, v, of the spectral line produced  for the transition of an electron from n = 8 to n = 4 in a Bohr hydrogen atom ?
Answer: 1.542E14 (1/s)


4. If the electron in a hydrogen atom undergoes a transition from an n = 5 level to an n = 3 level, what is the wavelength of the radiation emitted?
Answer:1.28E-6 m


5. What is the shortest wavelength of light that can be emitted by a hydrogen atom that has an initial configuration of 4p1
Answer: 9.73E-8 m


6. What must be the velocity, in meters per second, of a beam of electrons if they are to display a de Broglie wavelength of 9.41 μm?
Answer: 77.3m/s


7. Consider the 6f orbital of a hydrogen atom.

 a) How many different 6f orbitals are there?  Answer: 7

 b) How many radial nodes are there?   Answer: 2  

 c) How many angular nodes are there? (i.e. How many nodal planes or surfaces, not including radial nodes?)  Answer: 3

8. The radial probability distribution for an orbital in the n = 5 shell is shown below.

What type of orbital is it?

Answer: 5d








9.
a)  It takes _________  electrons to fill the 4d subshell of an atom.  Answer: 10
b) It takes __________ electrons to fill the n=4 shell of an atom.  Answer: 32

10. For a V atom in its ground electronic state:

 a) How many electrons are there in the 4s orbital?  Answer: 2

 b) How many electrons are there in the 3d orbitals?  Answer: 3 

 c) How many electrons are there in the 4p orbitals?  Answer:  0

 d) How many unpaired electrons are there?   Answer:  3

 e) To what block of the periodic table does V belong?  Answer: d

11.  For the following groups of elements, select the one that has the property noted.

a) The largest atom. Answer: Ba

• Cr
• l
• Ca
• Ba
• Pb
• Nb

(b) The lowest first ionization energy.  Answer: Cs

• Mg
• Si
• Sb
• ln
• F
• Cs

(c) The most negative electron affinity.   Answer: Cl  

• Ga
• Te
• Rb
• Sr
• Cl
• Bi

(d) The largest number of unpaired electrons.   Answer: As  

• Te2−
• Br
• As
• Hf3+
• Sr2+
• La3+

12. What is the ground-state electron configuration of the Fe3+ ion? [Ar] 4s2 3d6

Answer:  [Ar] 3d5

• [Ar] 4d5
• [Ar] 4s2 4d3
• [Ar] 3d5
• [Ar] 4s2 3d3

13. Which of the following is/are paramagnetic in the ground electronic state? 

Answer: V3+,Ti,S,Fe

• V3+
• Na-
• Zn2+
• Ti
• S
• Fe

14. Which atom has the largest covalent radius?

Answer: As

• P
• S
• Se
• O
• As

15. Which choices represents the correct ordering of radii from smallest to largest?

Answer:  Na+ < K+ < Rb+ < Ba2+

• O < Se2− < S < Te2−
• Na+ < K+ < Rb+ < Ba2+
• S < S2− < P3− < P
• Mg2+ < Al3+ < Si4+ < P5+

16. Which of the following species is diamagnetic?

Answer: Ba

• Te
• Ba
• Ti
• Pb

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