UNIT 5 EXTRA PROBLEMS FOR THE WEBSITE
(Honors & Regents): Electron Configuration and
Periodic Table.
[Regents students please note that questions on nuclear chemistry may be
found on unit 2 extra problems, in the Honors section, including on the
sample test]
1. Does the energy of a photon increase or decrease with increasing wavelength?
2. What is the maximum number of electrons that can occupy each of the following
subshells: 1s, 2p, 3d, and 4f?
3. Each of the following electron configurations represents the valence-shell
configuration for an atom of an element in the periodic table. For each, what is the
element, and in what period does it belong?
a) 4s2 4p2 b) 3d6 4s2 c) 6s1 d) 2s2 2p5 e) 3d104s2
4. Which of the following electron configurations for neutral atoms correspond to ground
states, and which correspond to excited states?
a) 1s12s1 b) [Ar]4s1 c) [Ar]3d6 d) [Xe]6s25d106p3
5. Arrange the following atoms in order of increasing atomic size: (a) Mg, Ca, Sr (b) B,
F, Ge, Pb
6. Which member of each pair is expected to have the more metallic character: (a) Na or
Rb; (b) K or Ca; (c) Pb or F; (d) C or Sn?
7. Which of the following are solids at room temperature, and which are gases? (a) CO2
(b) BaO (c) CuO (d) F2 (e) NO
8. Classify each as a metal, metalloid, or nonmetal: (a) Si (b) Ba (c) Au (d) Xe (e) I
9. Based on their positions in the periodic table, select the atom of each pair that has the
larger value of the indicated atomic property:
(a) ionization energy, Mg or Cl (b) ionization energy, Na or Mg (c) electronegativity, Cl
or Br (d) atomic radius, K or Cs (e) atomic radius, Se or Br
The following problems are for Honors only:
10. Calculate the wavelength of electromagnetic radiation that has a frequency of 9.22 x
1017 s-1.
11. Calculate the energy of an X-ray photon with a wavelength of 3.00 x 10-10 m.
12. Write the shorthand notation (for example, 2s) for the orbitals described by the
following quantum numbers: (a) n = 2, l = 1, ml = 0 (b) n = 3, l = 2, ml = 1 (c) n = 4, l = 3,
ml = 2
Answers: 1. decrease , 2. [2;6;10;14] , 3. (Ge; Fe; Cs; F; Zn) , 4. ground (b) and (d) ;
excited (a) and (c) , 5. (a) Mg<Ca<Sr ; (b) F<B<Ge<Pb , 6. (Rb; K; Pb; Sn) , 7. (a)
gas (b) solid (c) solid (d) gas (e) gas , 8. (a) metalloid (b) metal (c) metal (d) nonmetal
(e) nonmetal , 9. (a) Cl (b) Mg (c) Cl (d) Cs (e) Se , 10. 3.25 x 10-10 m , 11. 6.63 x 10-16
J , 12. (a) 2p (b) 3d (c) 4f
The following is an example of an Honors test for Unit 5:
Multiple Choice:-1. Which of the atoms below would not be paramagnetic in its ground state?
a) Mn b) Gd c) C d) F e) Be
2. The valence shell configuration of an atom is 5s25p2. What is the atom's chemical
symbol?a) At b) Bi c) Br d) As e) Sn
3. Which has a different electron configuration than the others?
a) Na+ b) N-3 c) F- d) Ar e) Al+3
4. Which is the correct orbital diagram for the outer shell of an atom of Sn? (The symbol
x stands for an electron of one spin; 0 stands for an electron of the opposite spin).
a) xo x_ o_ __ b) x_ x_ x_ x_ c) xo x_ x_ __ d) xo xo __ __ e) xx oo __ __
5. The following electronic transmissions occur when lithium atoms are sprayed into a
flame. ("4s ---> 3p" means an electronic transition from a 4s to a 3p orbital). The various
steps are numbered for identification:
I ............II ...........III ..........IV ...........V
2s -----> 2p -----> 3d -----> 3p -----> 4s -----> 2p
Which of them would result in the emission of light?
a) steps III and V only b) steps I, II, and V b) only step III d) all the steps e) steps III, IV,
and V
6. Below are five pairs of atoms and ions. In which pair is the larger of the two species
written first?
a) S-2, S b) Cu+2, Cu c) O, O-2 d) Ca+2, Ca e) Cr+3, Cr
7. Which of the following is not an allowed set of quantum numbers for ab electron in an
atom?
a) n = 3, l = 3, ml = -2, ms = 1/2 , b) n = 4, l = 3, ml = -3, ms = 1/2 , c) n = 2, l = 0, ml = 0,
ms = -1/2 , d) n = 3, l = 2, ml = -1, ms = 1/2 , e) n = 3, l = 0, ml = 0, ms = 1/2
8. The element bromine is a
a) period 3 alkali metal b) period 3 noble gas c) period 4 halogen d) period 4 transition
metal
9. The periodic law states that there is a periodic repetition of the physical and chemical
properties of the elements
a) when they are arranged in order of increasing mass , b) if only metals are considered ,
c) when they are arranged in order of increasing radii , d) when they are arranged in order
of increasing atomic number
10. Stable electron configurations are likely to contain:
a) filled energy levels , b) fewer electrons than unstable configurations , c) unfilled s
orbitals , d) only electrons with a clockwise spin
11. What is the frequency of light that has a wavelength of 600 nm?
a) 5.00 x 1012 Hz , b) 1.33 x 1012 Hz , c) 2.00 x 1015 Hz , d) 5.00 x 1014 Hz , e) 2.00 x 1013
Hz
12. Of the following atoms, which one has the smallest first ionization energy?
a) boron b) carbon c) aluminum d) silicon
13. Atomic size generally
a) increases as you move from left to right across the Periodic Table , b) decreases as you
move from left to right across a period , c) remains constant within a period , d)
generallly decreases as you move from top to bottom down the table
14. What is the energy, in joules, of a photon that has a frequency of 8.0 x 1018 Hz?
a) 3.4 x 10 -14 J , b) 5.6 x 10-15 J , c) 2.1 x 10 -13 J , d) 6.5 x 10-15 J , e) 1.32 x 10-19 J
15. The number of unpaired electrons in the Co+3 ion is
a) 6 b) 3 c) 4 d) 1 e) 5
16. The electron shell configuration for potassium is
a) 2,2,8,1 b) 2,10,6,1 c) 2,8,9 d) 2,8,8,1 e) 8,8,3
17. The maximum number of electrons that can occupy a p subshell is
a) 2 b) 3 c) 6 d) 8
18. Proceding from top to bottom down Group 14, the metallic character of the elements
a) increases b) decreases c) remains the same
19. Which of the following electron transitions would emit radiation of the highest
frequency?
a) 4s ---> 3s b) 4s ---> 3d c) 4s ---> 2s d) 3d ---> 4s
20. Which represents a possible excited state configuration for an atom of potassium?
a) 1s22s23s23p64s1 b) 1s22s22p63s23p64s1 c) 1s22s22p63s23p54s2 d) 1s22s22p63s23p7
Problems:
21. Supply the following information for the neutral atom of Arsenic in the ground state:
75
33As
a) atomic number ______________________
b) number of electrons __________________
c) electron configuration _________________
d) number of valence electrons ____________
e) number of filled orbitals ________________
f) orbital diagram for the valence level
____________________________________________
22. Consider the following elements: sodium, magnesium, argon, aluminum, sulfur,
phosphorus, silicon, chlorine
a) Arrange these elements in order of increasing atomic radius
b) Arrange these elements in order of increasing electronegativity
c) Arrange these elements in order of increasing metallic character
23 a) Write out the electron configuration for the Fe+2 ion
b) Why is the third ionization energy for magnesium more than ten times the value for the
first ionization energy?
c) What are the four quantum numbers used to describe the 15th electron of an atom of
sulfur in the ground state?
d) Why is a Ca+2 ion smaller than a Cl- ion?
Answers:
1e , 2e , 3d , 4c , 5a , 6a , 7a , 8c , 9d , 10a , 11d , 12c , 13b , 14b , 15c , 16d ,
17c , 18a , 19c , 20c
21 a) 33 , b) 33 , c) [Ar]4s23d104p3 , d) 5 , e) 15 , f) xo x_ x_ x_
22 a) Ar<Cl<S<P<Si<AL<Mg<Na , b) Na<Mg<Al<Si<P<Cl<Ar , c)
Ar<Cl<S<P<Si<Al<Mg<Na
23 a) [Ar]3d6 , b) removal of the third electron is breaking up a noble gas
configuration , c) 3,1,-1,+1/2 , d) they both have 18 electrons, but the p/eratio is greater for Ca+2