Chemistry
Graphing Lab
A GRAPHIC ILLUSTRATION OF THE PERIODIC LAW
In 1912 Moseley summarized the properties of the elements with relation to their atomic number in a law which
states: the properties of the elements are a periodic function of their atomic numbers.
In this exercise we shall study the relationship between the atomic numbers of the elements and some of their
physical properties. To do this we will compare, by means of graphs, the electonegativity, ionization energy,
and the atomic radius of the elements in the hydrogen, alkali-metal, nitrogen, oxygen, halogen, and noble gas
families. Note: Hydrogen is a single membered family.
The pertinent data are given in the table as follows:
(1) electronegativity vs. atomic #, (2) ionization energy vs. atomic #, (3) atomic radius vs. atomic #
Start with your graphing paper in the “landscape” orientation. Plot atomic number along the horizontal axis in
each case. Number consecutively between 1 & 19, then leave two spaces, number 33-37, leave two spaces,
then number 51-55.
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Plot each point and label it with the symbol of each element.
Connect the points representing consecutive elements by a solid line in pencil and use a dashed line to
complete the graph.
Connect the elements of the same family with solid lines, each in a different color.
Nitrogen Family = blue
Halogens = green
alkali metals = yellow
Oxygen Family = red
Noble Gases = gold
ELEMENT H He Li N O F Ne Na P S Cl Ar K As Se Br Kr Rb Sb Te I Xe Cs ATOMIC NUMBER ELECTRONEGATIVITY
1 2 3 7 8 9 10 11 15 16 17 18 19 33 34 35 36 37 51 52 53 54 55 2.20
0.98 3.04 3.44 3.98 0.93 2.19 2.58 3.16 0.82 2.18 2.55 2.96 0.82 2.05 2.1 2.66 0.79 IONIZATION ENERGY, ELECTRON VOLTS 13.6 24.6 5.4 14.5 13.6 17.4 23.6 5.1 11.0 10.4 13.0 15.8 4.3 10.5 9.8 11.8 14.0 4.2 8.6 9.0 10.4 12.1 3.9 ATOMIC RADIUS, ANGSTROMS, Å 0.37 0.32 1.23 0.74 0.74 0.72 0.69 1.57 1.10 1.04 0.99 0.97 2.03 1.21 1.17 1.14 1.10 2.16 1.41 1.37 1.33 1.30 2.35 Chemistry Write‐Up Name Graphing Lab Date ______________________Period ___ I.
Title: II.
Purpose: III.
Data: include your three labeled graphs attached to the back of this page. IV.
Analysis/Conclusion Questions. 1. What happens to the number of valence electrons (outermost electrons) as you go down a group? 2. What happens to the number of valence electrons as you go across a period? 3. Define the following terms: electronegativity, ionization energy and atomic radius. a.electronegativity = b. ionization energy = c. atomic radius = 4. Describe the trend in ionization energy as you go down a group and explain why the trend occurs. 5. Describe the trend in electronegativity as you go down a group and explain why the trend occurs. 6. Describe the trend in atomic radius as you go down a group and explain why the trend occurs. 7. Describe the trend in ionization energy as you go across a period and explain why the trend occurs. 8. Describe the trend in electronegativity as you go across a period and explain why the trend occurs. 9. Describe the trend in atomic radius as you go across a period and explain why the trend occurs.