Classification of Elements & Periodicity
Offer an electron to a gaseous atom and watch the energy meter. Almost every atom is hungry — it gulps the electron and releases energy. Only Be, Mg, N and the noble gases refuse. And nobody wants the second electron.
Electron offer karo — meter neeche/green gaya toh atom ne liya (energy released), upar/red gaya toh mana (absorbed). Doosra electron? Hamesha repulsion.
5 minutes · +4 right, −1 wrong (real NEET marking) · one global leaderboard.
Negative matlab atom electron lene par energy RELEASE karta hai — woh electron chahta hai (exothermic). Jitna zyada negative, utna zyada chahta. Positive matlab electron ghusane me energy LAGTI hai (endothermic) — atom mana kar raha hota hai.
F bahut chhota hai; uske compact 2p subshell me aane wale electron ko pehle se bhare electrons zyada repel karte hain. Cl bada hai, repulsion kam — isliye Cl (−349) F (−328) se zyada exothermic. Group 17 me Cl sabse −ve hoti hai.
Be aur Mg ka ns² fully-filled, N ka 2p³ half-filled, aur noble gases ka octet — ye sab extra stable configurations hain. Inme extra electron daalne ke liye energy deni padti hai, isliye ΔegH positive (endothermic).
Pehla electron lene ke baad atom −1 anion ban jata hai. Ab aane wala electron (−) aur anion (−) — same charge, isliye repulsion. Electron ko zabardasti ghusana padta hai, energy LAGTI hai. Isiliye O⁻ → O²⁻ ke liye +780 kJ/mol, aur O²⁻ banana overall endothermic hota hai.
Inme se sabse zyada negative (most exothermic) electron gain enthalpy kiski hoti hai?