To determine which element, sodium (Na) or aluminum (Al), has a larger atomic radius, we must consider their positions in the periodic table. Sodium is located in Group 1, while aluminum is in Group 13.
As we move from left to right across a period in the periodic table, the atomic radius generally decreases. This is because the number of protons in the nucleus increases, pulling the electrons closer to the nucleus due to the greater positive charge. Sodium is further to the left than aluminum, which suggests that it would have a larger atomic radius.
Furthermore, sodium has an atomic number of 11 and aluminum has an atomic number of 13. Sodium’s electron configuration ends in 3s1, while aluminum ends in 3p1. While aluminum has more total electrons than sodium, the increased nuclear charge in aluminum results in a stronger attraction between the nucleus and the electrons, particularly for the outermost electrons.
In conclusion, sodium has a larger atomic radius than aluminum. This is due to sodium’s position in the periodic table and the increased atomic number of aluminum, which leads to a greater effective nuclear charge that pulls its electrons closer, reducing the atomic radius.