1. Consider the Diagram Below…
Number of core electrons increases
Number of protons increases
Number of core electrons stay the same
Nucleus
Nucleus
Number of core electrons increases
Number of protons increases
Number of valence electrons stay the same
Nucleus

2. Answer the following questions in complete sentences in your notebook:
Consider any two main group atoms that are in the SAME group/family on the periodic table.
Which atom has a greater number of core electrons?
In which atom is the nuclear charge experienced by the valence electrons shielded to a greater degree by the core electrons?
In which atoms is the effective nuclear charge felt by the valence electrons least?
Repeat question #1, considering any two atoms that are in the SAME period on the periodic table.

3. Consider the trend in ionization energy
Define ionization energy.
Consider the two atoms that are found in the same family/group on the periodic table.
Which atom has the greater ionization energy?
Use the concepts of electron shielding and effective nuclear charge to explain this trend.
Consider the two atoms that are found in the same period on the periodic table.

4. Consider the trend in electronegativity
Define electronegativity.
Consider the two atoms that are found in the same family/group on the periodic table.
Which atom has the greater electronegativity?
Use the concepts of electron shielding and effective nuclear charge to explain this trend.
Consider the two atoms that are found in the same period on the periodic table.

5. Consider the trend in atomic radius
Define atomic radius.
Consider the two atoms that are found in the same family/group on the periodic table.
Which atom has the greater atomic radius?
Use the concepts of electron shielding and effective nuclear charge to explain this trend.
Consider the two atoms that are found in the same period on the periodic table.