[Verse 1] Covalent, metallic, van der Waals — three ways to measure size Down the group the shells stack up, radius multiplies Cross the period, protons pull tighter, clouds compress Nuclear charge winning the tug, the atom shrinks unless— Cátions ficam pequenos, ânions ficam enormes Na⁺ loses a shell, F⁻ swells past its old norms Isoelectronic series — same ten electrons, different pull Ne, Na⁺, Mg²⁺, F⁻, O²⁻ — more protons, smaller skull Rank them by the charge riding on that shared electron crowd More protons in the core, the smaller and the proud [Chorus] Descendo o grupo, o raio cresce, sobe a instabilidade Atravessando o período, aperta — essa é a verdade Bigger down, tighter across, that's the rule of the house But watch the breaks at groups thirteen, sixteen — they flip it all about [Verse 2] First ionization climbs the period like a rooftop stair Tighter grip on every valence, harder to pull one from there But beryllium to boron dips — the 2p sits looser than 2s Nitrogen to oxygen dips too — paired spins under stress Half-filled nitrogen's orbital sits stable, symmetric, calm Oxygen crams a pairing in, repulsion breaks the balm Successive IEs leap sky-high once you crack a filled-up shell That jump reveals the group — count the leaps and you can tell Electron affinity's mostly a release, an exhale, a gift Nitrogen's half-filled shell says no — stability won't shift Noble gases slam the door, their octets sealed for good Group two keeps its s-shell shut — no room, no neighborhood Fluorine's tiny orbital crowds any electron coming in Chlorine's got the elbow room, so chlorine's affinity wins [Chorus] [Verse 3] Pauling scale's from bond energy, Mulliken's from IE plus EA Allred-Rochow uses charge over radius squared, Allen's got his own way All four agree the climb goes rightward, fluorine wears the crown Cesium barely holds its electrons, loosest atom around Polarizability — big soft clouds bend, distort, and sway Small hard ions stay adamantine, refuse to give away Soft acids court soft bases, hard sticks to hard — that's HSAB's decree The metalloid staircase splits the metals from what's nonmetal-ly Boron, silicon, germanium, arsenic, tellurium walk that seam Oxidation states chase group number — mostly stick to the scheme Transition metals bend the rule, multiple states, no shame Thallium, lead, bismuth drop two low — the inert pair's to blame
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