Periodic Trends

Chemistry · आवर्ती प्रवृत्तियां · 15 facts

Atomic radius decreases left to right in period (more protons)

Atomic radius increases top to bottom in group (more shells)

Ionization energy: increases left to right; decreases top to bottom

Noble gases have highest ionization energy in period

Electron affinity generally increases left to right

Electronegativity: Fluorine highest; increases L to R, decreases T to B

Metallic character decreases L to R; increases T to B

Cs most electropositive; Fr most reactive metal(rare)

Metal reactivity increases down group; non-metal decreases

Valency across period: 1,2,3,4,3,2,1,0 (main group)

Pauling scale: F=4.0, O=3.5, N=3.0, C=2.5

Ionic radius: cations smaller, anions larger than parent atom

Shielding effect: inner electrons reduce nuclear attraction on outer electrons

Diagonal relationship: Li-Mg, Be-Al, B-Si show similar properties

Boiling point generally increases down group for metals (stronger metallic bonds)