What is the primary factor affecting the periodic trends in atomic size?

What is the primary factor affecting the periodic trends in atomic size?

Step 1: Understand that atoms are made of protons, neutrons, and electrons.
Step 2: Know that protons are in the nucleus and have a positive charge.
Step 3: Realize that electrons are outside the nucleus and have a negative charge.
Step 4: Learn about 'nuclear charge,' which is the total positive charge from protons in the nucleus.
Step 5: Understand that 'effective nuclear charge' is the charge that outer electrons actually feel, which is less than the total nuclear charge due to electron shielding.
Step 6: Know that 'electron shielding' happens when inner electrons block the outer electrons from feeling the full pull of the nucleus.
Step 7: Recognize that as you move down a group in the periodic table, more inner electron layers are added, increasing shielding.
Step 8: Understand that as you move across a period, the number of protons increases, but shielding does not increase as much, leading to a stronger pull on outer electrons.
Step 9: Conclude that the balance between effective nuclear charge and electron shielding is the primary factor affecting atomic size.

No concepts available.