Which element in each of the following pairs has the higher ionization energy? (a) As or Cl (b) Mg or Ba

Verified step by step guidance

1. Step 1: Understand the concept of ionization energy. Ionization energy is the energy required to remove an electron from an atom in its gaseous state. It generally increases across a period and decreases down a group in the periodic table.
2. Step 2: Analyze the position of As and Cl in the periodic table. Arsenic (As) is in group 15 and period 4, while Chlorine (Cl) is in group 17 and period 3.
3. Step 3: Apply the periodic trend for ionization energy to As and Cl. Since Cl is to the right of As in the same period, Cl has a higher ionization energy than As.
4. Step 4: Analyze the position of Mg and Ba in the periodic table. Magnesium (Mg) is in group 2 and period 3, while Barium (Ba) is in group 2 and period 6.
5. Step 5: Apply the periodic trend for ionization energy to Mg and Ba. Since Mg is above Ba in the same group, Mg has a higher ionization energy than Ba.