Zitsanzo za Mafunso Okhudza Ma Bond Oyambira a Mankhwala
Pendauluan
Chigwirizano cha mankhwala ndi mphamvu yomwe imagwirizanitsa maatomu mu molekyulu kapena chophatikizika. Kumvetsetsa zoyambira za mgwirizano wa mankhwala ndikofunikira kwa ophunzira a chemistry chifukwa kumayala maziko omvetsetsa machitidwe a mankhwala, kapangidwe ka mamolekyulu, ndi mawonekedwe a zinthu. Chigwirizano cha mankhwala chikhoza kugawidwa m'mitundu ingapo ikuluikulu: ma covalent bonds, ma ionic bonds, ma metallic bonds, ndi mphamvu za van der Waals. M'nkhaniyi, tikambirana zitsanzo zingapo za mavuto ndi mayankho awo kuti tithandize kumvetsetsa mfundo zoyambira za mgwirizano wa mankhwala.
Ma Ionic Bonds
Ma Ionic bonds amachitika pamene ma elekitironi amasamutsidwa kuchokera ku atomu imodzi kupita ku ina, zomwe zimapangitsa kuti pakhale ma positive ions (cations) ndi negative ions (anions). Chitsanzo chodziwika bwino ndi mgwirizano pakati pa sodium (Na) ndi chlorine (Cl) mu sodium chloride (NaCl).
Funso 1:
Fotokozani njira yopangira mgwirizano wa ionic pakati pa magnesium (Mg) ndi oxygen (O).
Kukambirana:
1. Magnesium ili ndi kapangidwe ka elekitironi ka [Ne] 3s², pomwe mpweya uli ndi kapangidwe ka elekitironi ka [He] 2s² 2p⁴.
2. Magnesium idzatulutsa ma elekitironi awiri kuchokera ku chipolopolo chake cha valence cha 3s² kuti ikwaniritse mawonekedwe okhazikika a elekitironi [Ne].
3. Mpweya wa okosijeni umalandira ma elekitironi awiri kuti adzaze 2p⁴ orbital kufika pa 2p⁶, zomwe zimapangitsa kuti ma elekitironi akhale okhazikika monga neon (Ne).
4. Magnesium ikatulutsa ma elekitironi awiri, imasintha kukhala Mg²⁺ ion, ndipo ikalandira ma elekitironi awiri, mpweya umasintha kukhala O²⁻ ion.
5. Ma charge osiyana pakati pa Mg²⁺ ndi O²⁻ amakokana, ndikupanga ionic bond MgO.
Mabungwe Ogwirizana
Chigwirizano cha covalent chimachitika pamene maatomu awiri amagawana ma elekitironi awiri. Chigwirizano cha covalent chingakhale chosakhala cha polar ngati ma elekitironi awiriwa akugawidwa mofanana kapena polar ngati ma elekitironi awiriwa akugawidwa mosiyana.
Funso 2:
Fotokozani kupangika kwa ma covalent bonds mu molekyulu yamadzi (H₂O).
Kukambirana:
1. Atomu ya okosijeni ili ndi ma elekitironi asanu ndi limodzi mu chipolopolo chake chakunja (kapangidwe [He] 2s² 2p⁴) ndipo imafunika ma elekitironi ena awiri kuti ifike pa octet.
2. Atomu iliyonse ya haidrojeni ili ndi elekitironi imodzi mu chipolopolo chakunja (kapangidwe ka 1s¹) ndipo imafunika elekitironi imodzi kuti ipange duplet.
3. Mpweya wa okosijeni udzagawana ma elekitironi ake ndi atomu iliyonse ya haidrojeni, pomwe maatomu a haidrojeni aliyense adzapereka elekitironi.
4. Izi zimapangitsa kuti pakhale ma covalent bond awiri pakati pa okosijeni ndi ma hydrogen awiri, zomwe zimapangitsa molekyulu ya H₂O yokhala ndi kapangidwe ka Lewis ka HOH.
Ma Bond a Chitsulo
Kugwirizana kwachitsulo kumachitika mu zitsulo, komwe kuli "nyanja" ya ma elekitironi osunthika omwe amayenda momasuka pakati pa ma ayoni achitsulo. Izi zimapangitsa zitsulo kukhala ndi mphamvu yabwino yoyendetsera magetsi ndi kutentha.
Funso 3:
Fotokozani chifukwa chake zitsulo monga mkuwa (Cu) zimatha kuyendetsa bwino magetsi.
Kukambirana:
1. Mu kapangidwe ka chitsulo, maatomu a mkuwa amazunguliridwa ndi mtambo wa ma elekitironi wosasunthika.
2. Ma electron awa samamangiriridwa ku atomu iliyonse ndipo amatha kuyenda momasuka mu kapangidwe ka chitsulocho.
3. Pamene mphamvu yamagetsi ikugwiritsidwa ntchito, ma elekitironi awa amatha kuyenda pamodzi mbali imodzi, zomwe zimathandiza kuti magetsi aziyenda.
4. Chifukwa chake, ma elekitironi aulere awa kapena delocalization zimapangitsa mkuwa ndi zitsulo zina kukhala ndi mphamvu zoyendetsa magetsi bwino.
Mphamvu ya Van der Waals
Mphamvu za Van der Waals ndi mphamvu zofooka zomwe zimachitika chifukwa cha kusakhazikika kwa kugawa kwa ma elekitironi mkati kapena pakati pa mamolekyu. Pali mitundu iwiri ikuluikulu: mphamvu za London (dispersion) ndi mphamvu za dipole-dipole.
Funso 4:
Fotokozani udindo wa mphamvu za Van der Waals mu gawo lamadzimadzi ndi lolimba la benzene (C₆H₆).
Kukambirana:
1. Mamolekyu a Benzene ndi mamolekyu omwe si a polar chifukwa ndi ofanana, kotero mphamvu za London (dispersion) ndi mphamvu zazikulu za Van der Waals.
2. Mphamvu za ku London zimayamba chifukwa cha kuyanjana pakati pa dipoles zomwe zimachitika nthawi yomweyo chifukwa cha kusinthasintha kwa magawidwe a ma elekitironi mu molekyulu ya benzene.
3. Ngakhale kuti mphamvu zimenezi ndi zofooka poyerekeza ndi ma covalent kapena ionic bonds, mphamvu zambiri za ku London zimatha kukhudza katundu wa mamolekyu.
pa magawo olimba ndi amadzimadzi.
4. Mu gawo lamadzimadzi, mphamvu za Van der Waals zimagwirizira mamolekyu pamodzi ngakhale kuti kuyenda kwa mamolekyu kukadali kwakukulu.
5. Mu gawo lolimba, mphamvu zimenezi zimathandiza kusunga dongosolo la mamolekyu lokonzedwa bwino.
Mafunso ndi Zokambirana Zowonjezera za Zitsanzo
Funso 5:
Fotokozani kupangika kwa ma polar covalent bonds mu molekyulu ya carbon dioxide (CO₂) ndi chifukwa chake molekyulu iyi si ya polar.
Kukambirana:
1. Mpweya uli ndi ma elekitironi anayi a valensi, pomwe mpweya uli ndi ma elekitironi asanu ndi limodzi a valensi.
2. Kuti akwaniritse mawonekedwe a octet, kaboni imafuna ma elekitironi awiri ndipo mpweya umafunika ma elekitironi awiri iliyonse.
3. Kaboni imapanga ma bond awiri a covalent okhala ndi maatomu awiri a okosijeni mbali zonse ziwiri (kapangidwe ka O=C=O).
4. Chigwirizano chilichonse cha covalent chimaphatikizapo kugawana ma elekitironi awiri pakati pa kaboni ndi mpweya.
5. Ngakhale kuti chomangira chilichonse cha C=O chili ndi polar (mpweya woipa kwambiri umakopa ma elekitironi mwamphamvu kwambiri), ma polarities awa ndi ofanana ndipo amasiyana mu dongosolo la CO₂ molecule, kotero kuti molekyu yonse siili polar.
Funso 6:
Nchifukwa chiyani molekyulu ya ammonia (NH₃) ili ndi ngodya yolumikizira yocheperako kuposa tetrahedron yoyenera?
Kukambirana:
1. Nayitrogeni mu ammonia ili ndi ma electron asanu a valence (kapangidwe [He] 2s² 2p³) ndipo imafunika ma electron ena atatu kuti ifike pa octet.
2. Nayitrogeni imapanga ma covalent bond atatu ndi ma atomu atatu a haidrojeni, zomwe zimasiya ma elekitironi awiriawiri pa nayitrogeni.
3. Tetrahedron yabwino kwambiri ili ndi ngodya ya bond ya 109.5°, koma chifukwa awiri okhawo amafuna malo ambiri ndipo amakankhira bond ya HNH pafupi ndi 107°.
4. Mphamvu yobwezera ya ma elekitironi awiriawiri imachepetsa ngodya ya bond poyerekeza ndi ngodya yoyenera ya tetrahedral.
Funso 7:
Chifukwa chiyani NaCl imasungunuka m'madzi koma I₂ siisungunuka?
Kukambirana:
1. NaCl ndi chinthu cha ionic chomwe chili ndi ma ioni a Na⁺ ndi Cl⁻. Madzi ndi chosungunulira cha polar chomwe chingalekanitse ma ioni awa kudzera mu mgwirizano wa ion-dipole.
2. NaCl ikasungunuka, ma ayoni a Na⁺ ndi Cl⁻ amazunguliridwa ndi mamolekyu amadzi omwe amakonza okha kuti akhazikitse mphamvu ya ma ayoni.
3. I₂ ndi molekyulu yopanda polar kotero siisungunuka bwino mu zosungunulira za polar monga madzi koma imasungunuka bwino mu zosungunulira zopanda polar malinga ndi mfundo yakuti "monga imasungunuka ngati".
Kutseka
Kumvetsetsa mfundo zoyambira za mgwirizano wa mankhwala kudzera mu kuthetsa mavuto ndi njira yothandiza yolimbikitsira malingaliro omwe adaphunziridwa kale. Pamwambapa, takambirana mitundu yosiyanasiyana ya mgwirizano wa mankhwala ndipo tapereka zitsanzo zokhudzana ndi mphamvu za ionic, covalent, metallic, ndi van der Waals. Mwa kugwiritsa ntchito ndikumvetsetsa mavutowa, tikukhulupirira kuti mudzamvetsetsa bwino mgwirizano wa mankhwala ndi momwe umagwiritsidwira ntchito m'malo osiyanasiyana.
