what is the trend in the atomic radii as the atomic number increases across a period? What is the exception to this trend?

I know the radius decreases as you go from left to right, but I can't figure the exception, I read somewhere that it's the noble gasses but I'm not sure.

The trend in atomic radii across a period is that they generally decrease as the atomic number increases from left to right. This is because, as you move across a period, the number of protons in the nucleus increases, resulting in a stronger attractive force pulling the electrons closer to the nucleus.

The exception to this trend is the group of noble gases. Noble gases are found in Group 18 (VIII A) of the periodic table, and they include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The atomic radii of noble gases do not follow the regular trend across a period. Instead, they have larger atomic radii compared to the elements in the same period.

This exception occurs because noble gases have completely filled outer electron shells. The filled electron shells create a repulsive force between the electrons, which counteracts the attractive force from the nucleus. As a result, the outermost electrons in noble gases are more shielded from the attractive pull of the nucleus, creating larger atomic radii compared to other elements in the same period.

The trend in atomic radii across a period is that the atomic radius generally decreases as the atomic number increases. This is because within a period, as you move from left to right, the number of protons in the nucleus increases, resulting in a greater positive charge in the nucleus. This increased positive charge pulls the electrons closer to the nucleus, making the atomic radius smaller.

The exception to this trend is the noble gases. Noble gases are located on the far right side of the periodic table. Despite having higher atomic numbers, the atomic radii of noble gases are larger compared to the elements in the same period. This is because noble gases have completely filled electron shells, making them more stable. The repulsion between the electrons in the filled shells causes the electron cloud to expand, leading to larger atomic radii compared to the adjacent elements in the period.