He aha nā Valence Electrons?
Pendahuluan
I loko o ke kemika, ʻo ka huaʻōlelo "valence electrons" kahi manaʻo nui e pono e hoʻomaopopo. ʻAʻole wale nā electrons Valence e pāʻani i kahi kuleana koʻikoʻi i ka hoʻoholo ʻana i nā waiwai kemika o kahi mea akā hoʻohuli pū kekahi i nā hopena kemika a me ke kūpaʻa o nā hui. E ʻimi hohonu kēia ʻatikala i ke ʻano o nā electrons valence, no ke aha lākou i koʻikoʻi ai, pehea lākou i hoʻolaha ʻia ai i loko o kahi ʻātoma, a pehea e hoʻopili ʻia ai kēia manaʻo ma nā ʻano like ʻole o ke kemika.
Ka Wehewehena o nā Electrons Valence
ʻO nā electrons Valence nā electrons i loaʻa i loko o ka pūpū waho loa o kahi ʻātoma a pili i ka hoʻokumu ʻana o nā pilina kemika. ʻOi aku ka ʻenehana, aia kēia mau electrons ma ka pae ikehu kiʻekiʻe loa o kahi ʻātoma a, no laila, kuleana no nā pilina ma waena o nā ʻātoma i ka hoʻokumu ʻana o nā molekala. Hiki ke loaʻa nā electrons Valence ma nā pūpū s a me p waho loa i ka hihia o nā mea kumu (A) a ma ka pūpū d waho loa i nā mea hoʻololi.
Ke Koʻikoʻi o nā Electrons Valence
He nui nā kuleana koʻikoʻi o nā electrons Valence i ka kemika:
1. Ka Hoʻokumu ʻana o nā Pili Kemika: Pili pololei nā electrons Valence i ka hoʻokumu ʻana o nā pili covalent, ionic, a me nā metala.
– Nā Hoʻopaʻa Covalent: I loko o kahi hui covalent, ʻelua mau ʻātoma e kaʻana like i kahi pālua o nā electrons valence. No ka laʻana, i loko o ka molekala H2O (wai), kaʻana like kahi ʻātoma hydrogen i nā electrons me kahi ʻātoma oxygen.
– Hoʻopili Ionic: I loko o nā hui ionic, hoʻoili ʻia nā electrons valence mai kekahi ʻātoma i kekahi ʻātoma ʻē aʻe, e hana ana i nā cations a me nā anions. No ka laʻana, i loko o ka sodium chloride (paʻakai), hāʻawi ka sodium i kāna mau electrons i ka chlorine.
– Hoʻopaʻa Metallic: I ka hoʻopaʻa metala, hiki i nā electrons valence ke neʻe manuahi ma waena o nā ions metala, e hana ana i kahi ʻano kristal metala ikaika a kuleana no nā waiwai e like me ka conductivity uila a me ka thermal.
2. Ka Hana Kemika: Hoʻoholo nā electrons Valence i ke ʻano o ka hana ʻana o kahi mea me nā mea ʻē aʻe. ʻO ka maʻalahi o ka nalowale ʻana, ka loaʻa ʻana, a i ʻole ka kaʻana like ʻana o kahi ʻātoma i nā electrons valence, ʻoi aku ka pane ʻana o ka mea. No ka laʻana, he pane nui nā metala alkali (e like me ka sodium) no ka mea hoʻokahi wale nō electron valence hiki ke nalowale maʻalahi.
3. Nā ʻAno Kino a me nā Kemika: Hoʻopili nā electrons Valence i nā ʻano kino (e like me ka heheʻe ʻana a me nā kiko paila) a me nā ʻano kemika (e like me ka acidity a i ʻole ka basicity) o kahi hui. No ka laʻana, ʻoi aku ka paʻa o nā ʻātoma me nā hoʻonohonoho electron valence i piha piha a emi iki ka pane ʻana.
Ka Hoʻokaʻawale ʻana o nā Elekona Valence
Aia nā electrons valence ma ka pūpū waho loa o kahi ʻātoma a hiki ke ʻike ʻia me ka hoʻohana ʻana i ka papa periodic. ʻO ka helu hui (kolamu kū) ma ka papa periodic e hōʻike ana i ka helu o nā electrons valence i loaʻa i kahi mea.
– Nā Hui Nui: I ke ʻano o nā mea e pili ana i ka hui nui (A), pili ka helu hui i ka helu o nā electrons valence. No ka laʻana, he hoʻokahi electron valence ko nā mea i loko o ka hui 1A (e like me ka hydrogen a me ka lithium). ʻEhiku electrons valence ko nā mea i loko o ka hui 7A (e like me ka fluorine a me ka chlorine).
– Nā ʻElemene Hoʻololi: No nā ʻelemene hoʻololi, ʻoi aku ka paʻakikī o ka helu o nā electrons valence no ka mea pili lākou i ka subshell d. ʻOiai aia nā ʻokoʻa, ma ke ʻano laulā, loaʻa i nā ʻelemene hoʻololi ʻelua mau electrons valence mai ka subshell s waho loa a me kekahi mau mea hou aʻe mai ka subshell d.
Hoʻonohonoho ʻana o ka Valence Electron
Hiki ke hoʻoholo ʻia ke ʻano o nā electron valence ma ke kākau ʻana i ke ʻano piha o nā electron o kahi ʻātoma a me ka ʻike ʻana i nā electrons ma ka pūpū waho loa. Eia kekahi laʻana:
– ʻĀtoma Chlorine (Cl): ʻO ka helu atomika o ka chlorine he 17. ʻO kona hoʻonohonoho electron he 1s² 2s² 2p⁶ 3s² 3p⁵. ʻO nā electrons valence o ka chlorine he 3s² 3p⁵, no laila he ʻehiku mau electrons valence ko ka chlorine.
– ʻĀtoma Potassium (K): ʻO 19 ka helu ʻātoma o Potassium. ʻO kona hoʻonohonoho ʻana o nā electrons he 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹. ʻO 4s¹ ka electron valence o Potassium, no laila hoʻokahi electron valence ko ka potassium e hoʻokuʻu maʻalahi ʻia.
Nā Laʻana a me nā Hoʻohana o nā Electrons Valence
1. Nā Hana ʻAkika-Kumu: I nā hana ʻakika-kumu, neʻe pinepine nā protons (H⁺) mai ka waikawa a i ke kumu, kahi e pili ana i ka launa pū ʻana o nā electrons valence. Loaʻa i nā waikawa e like me HCl nā electrons valence e hoʻokuʻu maʻalahi ʻia, ʻoiai ʻo nā kumu e like me NH3 he mau electrons valence e hiki ke huki i nā protons.
2. Ka Hoʻokele Uila: Loaʻa i nā metala e like me ke keleawe a me ka alumini nā electrons valence e wehe a hiki ke neʻe manuahi, e ʻae ana i ka metala e hoʻokele maikaʻi i ka uila.
3. Pi Bond a me Sigma Bond: I loko o ke kemika organik, hoʻokumu ʻia nā pilina pi a me sigma ma o ka launa pū ʻana o nā electrons valence. No ka laʻana, i loko o ka ethylene (C2H4), ʻo ka pilina pālua ma waena o nā ʻātoma kalapona e pili ana i hoʻokahi pilina sigma a me hoʻokahi pilina pi, i hoʻokumu ʻia kēlā me kēia mai nā electrons valence.
4. Nā mea hoʻouluulu: I ka catalysis, inā he homogeneous a heterogeneous paha, launa pū nā electrons valence o ka mea hoʻouluulu me nā mea hana e hoʻohaʻahaʻa i ka ikehu hoʻāla o ka hopena. ʻO kahi laʻana maʻamau ka hoʻohana ʻana i ka platinum ma ke ʻano he mea hoʻouluulu i nā hopena hydrogenation.
Ka hopena
ʻO nā electrons Valence kahi manaʻo koʻikoʻi i ka kemika e kōkua i ka wehewehe ʻana i kekahi mau hanana, me ka reactivity kemika, nā waiwai kino o nā hui, a me nā ʻano hana hopena. ʻO ka hoʻomaopopo ʻana i nā electrons valence a me ko lākou hoʻolaha ʻana i loko o nā ʻātoma he mea nui ia no ka hoʻomaopopo ʻana pehea e launa pū ai nā mea a me nā hui me kekahi. He mea nui kēia ʻaʻole wale no ka kemika kumu akā no nā noi hana i ka ʻepekema mea, biochemistry, a me nā ʻepekema i hoʻopili ʻia. Ma ka hoʻolaha ʻana i kēia manaʻo, e hiki i nā kānaka ʻepekema a me nā haumāna ke hoʻomaopopo maikaʻi a hoʻohana i nā waiwai kemika no nā ʻano ʻepekema a me nā ʻoihana like ʻole.
