How does the first ionization energy typically change across a period from left to right and down a group?
Decreases across a period, increases down a group
Increases across a period, decreases down a group
Increases across a period, increases down a group
Decreases across a period, decreases down a group
📝 Detailed explanation
Across a period, nuclear charge increases while shielding remains relatively constant, pulling electrons tighter (higher IE). Down a group, the outermost electrons are further from the nucleus and more shielded, making them easier to remove (lower IE).
