Periodic Law Graphing ActivityName ______

Date ______Period ______

A) Atomic Radius

  1. Atomic radius is measured in a unit called angstroms,Å. Define atomic radius. ______
  1. The atomic radii of the elements from Group 1 are Li, 1.52 Å; Na, 1.86 Å; K, 2.27 Å;

Rb, 2.48 Å; Cs, 2.66 Å. Plot these radii on the graph below.

Li Na K Rb Cs

Group 1 (IA) Elements (Increasing Atomic Number →)

  1. Trend: Down a group, as atomic number increases, atomic radius ______.
  1. Explain the trend: ______
  1. The atomic radii of the elements from Period 3 are Na, 1.86 Å; Mg, 1.60 Å; Al, 1.43 Å;

Si, 1.17 Å; P, 1.10 Å; S, 1.04 Å; Cl, 0.99 Å. Plot these radii on the graph below.

Na Mg Al Si P S Cl

Period 3 Elements (Increasing Atomic Number →)

  1. Trend: Across a period, as atomic number increases, atomic radius______.
  1. Explainthis trend: ______

B) Ionization Energy

  1. Define first ionization energy. ______
  1. What are second, third, and other successive ionization energies? ______
  1. The first ionization energies for the elements in Group 2 are Be, 900 kJ/mol; Mg, 738 kJ/mol; Ca, 590 kJ/mol; Sr, 550 kJ/mol; Ba, 503 kJ/mol. Plot these energies on the graph below.

Be Mg Ca Sr Ba

Group 2 (IIA) Elements (Increasing Atomic Number →)

  1. Trend: Down a group, as atomic number increases, 1st ionization energy ______.
  1. Explain this trend: ______
  1. The first ionization energies for the elements in Period 2 are Li, 520 kJ/mol; Be, 900 kJ/mol;

B, 801 kJ/mol; C, 1087 kJ/mol; N, 1402 kJ/mol; O, 1314 kJ/mol; F, 1681 kJ/mol.

Plot these energies on the graph below.

Li Be B C N O F

Period 3 Elements (Increasing Atomic Number →)

  1. Trend: Across a period, as atomic number increases, 1st ionization energy ______.
  1. Explain this trend and any irregularities: ______

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C) Electronegativity

  1. Define electronegativity. ______

______

  1. The electronegativity values for elements in Group 2 are Be 1.50; Mg, 1.29; Ca, 1.02; Sr, 0.97; Ba, 0.93. Plot these electronegativities on the graph below.

Be Mg Ca Sr Ba

Group 2 (IIA) Elements (Increasing Atomic Number →)

  1. Trend: Down a group, as atomic number increases, electronegativity______.
  1. Explain this trend: ______
  1. The electronegativity values for elements in Period 2 are Li, 0.96; Be, 1.50; B, 2.02; C, 2.56; N, 2.81; O, 3.37; F, 4.00. Plot these electronegativities on the graph below.

Li Be B C N O F

Period 2 Elements (Increasing Atomic Number →)

  1. Trend: Across a period, as atomic number increases, electronegativity______.
  1. Explain this trend: ______

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