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What is atomic radius?

Size of an atom from nucleus to outermost electrons.

What defines the atomic radius trend?

Increases down a group, decreases across a period.

Why does atomic radius increase down a group?

Additional electron energy levels make atoms larger.

Why does atomic radius decrease across a period?

Increased protons pull electrons closer to the nucleus.

What is ionization energy?

Energy needed to remove an electron from an atom.

What defines the ionization energy trend?

Increases across a period, decreases down a group.

Why does ionization energy increase across the periodic table?

Nuclear charge increases, holding electrons more tightly.

Why does ionization energy decrease down a group?

Electrons are farther from the nucleus, easier to remove.

What is electronegativity?

Ability of an atom to attract electrons in a bond.

What defines the electronegativity trend?

Increases across a period, decreases down a group.

Why does electronegativity increase across a period?

Stronger attraction for electrons due to increasing nuclear charge.

What is the shielding effect?

Inner electrons block nuclear attraction on outer electrons.

What is metallic character?

Tendency of an element to lose electrons like a metal.

What defines the metallic character trend?

Increases down a group, decreases across a period.

Why does metal reactivity increase down a group?

Electrons are easier to lose as atomic size increases.

Why does nonmetal reactivity increase up a group?

Atoms gain electrons more easily as size decreases.

What is the general periodic trend summary?

Atomic radius increases down and left; ionization energy and electronegativity increase up and right.