Cov khoom yog tsim los ntawm cov molecules, cov molecules yog tsim los ntawm cov atoms, thiab cov atoms muaj cov electrons tsis zoo thiab cov nqi zoo protons. Raws li ib txwm muaj, tus naj npawb ntawm protons thiab electrons nyob rau hauv ib lub atom yog sib npaug, uas ua rau ib tug nruab nrab nqi. Txawm li cas los xij, electrons orbiting lub atomic nucleus tuaj yeem raug tso tawm ntawm lawv lub orbits los ntawm sab nraud quab yuam, tawm hauv lawv cov qub atom thiab nkag mus rau lwm lub atom (B). Atom A, tsis muaj electrons, ua tau zoo thiab hu ua cation; atom B, tau txais electrons, ua tsis zoo them thiab hu ua anion.
Qhov ua rau ntawm qhov tsis sib npaug ntawm cov khoom siv hluav taws xob no yog kev tso tawm ntawm cov hluav taws xob los ntawm lawv cov orbits los ntawm sab nraud quab yuam. Cov rog no tuaj yeem suav nrog ntau hom zog (xws li lub zog kinetic, lub zog muaj peev xwm, lub zog thermal, lub zog tshuaj, thiab lwm yam). Nyob rau hauv lub neej txhua hnub, hluav taws xob zoo li qub yog tsim thaum ob yam khoom ntawm cov khoom sib txawv tuaj rau hauv kev sib cuag thiab ces sib cais.
Thaum ob yam khoom sib txawv tuaj rau hauv kev sib cuag, ib qho khoom poob qee qhov nqi (piv txwv li, cov khoom siv hluav taws xob hloov mus rau lwm qhov, ua rau nws muaj txiaj ntsig zoo), thaum lwm yam khoom tau txais qee cov khoom siv hluav taws xob thiab ua rau tsis zoo. Yog tias cov nqi them tsis yooj yim rau nruab nrab thaum sib cais, lawv sib sau ua ke, ua rau cov khoom ua kom raug nqi. Yog li ntawd, ib yam khoom yuav tau txais hluav taws xob zoo li qub thaum nws los rau hauv kev sib cuag nrog thiab sib cais los ntawm lwm yam khoom. Kev tshem tawm cov yeeb yaj kiab yas tawm ntawm ib qho khoom yog ib qho piv txwv ntawm "kev sib cuag- sib cais" them, thiab cov hluav taws xob zoo li qub tau tsim thaum tshem khaub ncaws hauv lub neej txhua hnub kuj yog "kev sib cuag- sib cais" them.
