PERIODIC TRENDS

Electronegativity is the ability of an atom to attract electrons in a chemical bond. It increases from left to right across a period and decreases from top to bottom within a group.

Atomic radius increases down a group because more shells (energy levels) are added, which increases the distance between the nucleus and the outermost electrons.

Radon (Rn) has the largest atomic radius in Group 18.

Atomic radius decreases from left to right across a period due to the increase in the number of protons, which increases the attraction to electrons.

Potassium (K) has the largest atomic radius in Period 4.

Atomic radius is the distance from the nucleus of an atom to the outermost shell of electrons.

Ionization energy generally increases from left to right across a period.

Ionization energy decreases down a group due to increased distance between the nucleus and the outermost electrons, making them easier to remove.

Generally, elements with high electronegativity also have high ionization energy, as both properties are related to the attraction of electrons.

Noble gases have complete valence shells, making them stable and generally unreactive, which affects trends in electronegativity and ionization energy.