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Chemistry LibreTexts

Building Atoms with Quantum Leaps 1 (Worksheet)

Name: ______________________________

Section: _____________________________

Student ID#:__________________________

Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.

1.    Complete the chart below by entering all possible values for the quantum numbers. The first line is completed as an example.

n l ml ms
1 0  0 +½, ½


Consider an atom of beryllium, which has two valence electrons. The quantum numbers for one of the valence electrons is n = 2, l = 0, ml= 0, and ms = +½ . What are the quantum numbers for the other valence electron?

2.    The ground-state electron configuration for the single electron in the hydrogen atom is 1s1. What are the values of the ml and ms quantum numbers for this electron?

3.    The quantum numbers for one of the two electrons of helium are n = 1, l = 0, ml = 0, and ms = –½. What are the quantum numbers for the other valence electron? Write the electron configuration for helium.

4.    What are the maximum number of electrons in an atom that can have when n = 1 and when n = 2? Explain.

5.    Work with three other students. Count off atomic numbers from 1 to 36, rotating among the members of your group.

    Write the full ground-state electron configuration for each of your nine elements.

6.    Begin by assigning one of each of the following elements to each group member:
    carbon, nitrogen, fluorine, neon, sodium, aluminum, phosphorus, chlorine, iron (there should be more elements in this list than group members; you may omit an element or two, as necessary). Each person should complete the following five steps for their element:

  • Step 1:    Write the electron configuration of the element. This can be copied from Question 5.
  • Step 2:    Prepare a chart similar to the one shown in the example below, giving the values of each of the four quantum numbers for each electron in the atom.
  • Step 3:    Fill in all of the items in the chart.
  • Step 4:    Create an energy level diagram for your element. Use a line to represent an orbital, and use up and down arrows to represent electrons in each orbital.
  • Step 5:    Fill in the energy level diagram.

    Boron is provided as an example.

    Step 1: Electron configuration

    B: 1s22s22p1

    Steps 2 and 3: Chart of quantum numbers

n    l    ml    ms
1    0    0    + ½

1    0    0    – ½

2    0    0    + ½

2    0    0    – ½

2    1    –1    + ½

Steps 4 and 5: Energy level diagram

2p          l   _____   _____
2s         l
1s         l

Electron configuration

Chart of quantum numbers

n    l    ml    ms

Energy level diagram


7.    Answer each of the following:

    a)  How many 3p electrons does a chlorine atom have?

    b)  Give the complete set of quantum numbers for all of the chlorine 3p electrons.

    c)  How many d electrons does an iron atom have?

    d)  How many unpaired electrons are in a chlorine atom, an iron atom, and a nitrogen atom?

Many substances exhibit no magnetic properties except in the presence of a magnetic field. Substances with all paired electrons are weakly repelled by a magnetic field. These substances are called diamagnetic. Other substances are attracted to a magnetic field and are called paramagnetic. This property is the result of unpaired electrons.

8.    Which of the following do you expect to be paramagnetic? Explain how you reach your conclusions.

    a) K

    b) Ba2+

    c) Fe2+

    d) Fe3+

    e) F

    f) F

    g) Ni2+

9.    For each of the following pairs, determine the atom with (i) the largest radius, (ii) the greatest first ionization energy, and (iii) the smallest electron affinity. Explain your reasoning in each case.

a)  F or K

b)  O or Si

c)  Li or Cs

d)  F or As

10.    Rank the following atoms by (1) increasing size, (2) decreasing first ionization energy and (3) decreasing electronegativity:  K, Cs, F, Si

(1) ____ <  ____ < ____ < ____

(2) ____ >  ____ > ____ > ____

(3) ____ >  ____ > ____ > ____

11.    Rank the following isoelectronic ions by (1) increasing size, (2) Identify each as being either Paramagnetic or Diamagnetic: F-, Na+, N3-, Mg2+

(1)  ____ <  ____ < ____ < ____

(2) Paramagnetic or Diamagnetic:

F-     ____

Na+    ____
N3-    ____
Mg2+    ____