Order the elements in each set from the smallest to largest first ionization energy. (a) Na, I, P (b) P, Sr, Mg (c) Ca, Cs, Se

Verified step by step guidance

1. Step 1: Understand the concept of ionization energy, which is the energy required to remove an electron from a gaseous atom or ion. Generally, ionization energy increases across a period (left to right) and decreases down a group (top to bottom) in the periodic table.
2. Step 2: For set (a) Na, I, P: Locate these elements on the periodic table. Na (Sodium) is in Group 1, I (Iodine) is in Group 17, and P (Phosphorus) is in Group 15. Consider their positions: Na is in Period 3, P is also in Period 3, and I is in Period 5.
3. Step 3: For set (b) P, Sr, Mg: Locate these elements on the periodic table. P (Phosphorus) is in Group 15, Sr (Strontium) is in Group 2, and Mg (Magnesium) is in Group 2. Consider their positions: P is in Period 3, Mg is in Period 3, and Sr is in Period 5.
4. Step 4: For set (c) Ca, Cs, Se: Locate these elements on the periodic table. Ca (Calcium) is in Group 2, Cs (Cesium) is in Group 1, and Se (Selenium) is in Group 16. Consider their positions: Ca is in Period 4, Se is in Period 4, and Cs is in Period 6.
5. Step 5: Apply the periodic trends: For each set, compare the elements based on their group and period positions to determine the order from smallest to largest ionization energy. Remember that elements further to the right and higher up in the periodic table generally have higher ionization energies.