I really don't understand what this is asking... please help.
1.) As you move left to right across the period, there are two elements that instead show a decrease in ionization energy. Identify these elements and explain why for each.
2.) Arrange Na+,Ca2+, Cl- in order of increasing ionic size. Explain.
3.) Arrange Si, F, C from least exothermic electron affinity to most. Explain.