Answer
Calcium and barium are both located in Group 2A. Atomic radii increases down a group. Therefore, barium is the larger atom.
Silicon and sulfur are both located in Period 3. Atomic radii decreases across a period. Therefore, silicon is the larger atom.
Sodium
Work Step by Step
Calcium and barium are both located in Group 2A. Atomic radii increases down a group. Therefore, barium is the larger atom.
Silicon and sulfur are both located in Period 3. Atomic radii decreases across a period. Therefore, silicon is the larger atom.
Sodium
