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Transcript of Lewis
IKATAN KIMIA
STRUKTUR LEWIS & MUATAN FORMAL
Sifat Atom
Three types of bonding result from the three ways these two types of atoms can combine: - metal with nonmetal, - nonmetal with nonmetal, and - metal with metal
1 . Metal with nonmetal: electron transfer and ionic bonding. 2. Nonmetal with nonmetal: electron sharing and covalent bonding. 3. Metal with metal: electron pooling and metallic bonding.
Struktur Lewis Menggambarkan ikatan kimia antar atom dalam
molekul berdasarkan simbol elektron valensi atomnya. Struktur Lewis memudahkan untuk menduga
bentuk molekul. Diperkenalkan oleh Gilbert N. Lewis (1875-1946),
seorang ahli kimia dari Amerika.
Simbol Lewis untuk unsur golongan utama
Langkah-langkah : Menentukan atom mana yang saling melekat
(bentuk penyusunan yang simetris) Hitung elektron valensi atom Tempatkan satu pasang elektron dalam setiap ikatan Lengkapi bentuk oktet dari ikatan ke atom pusat
Hydrogen atoms form one bond. Carbon atoms form four bonds. Nitrogen atoms form three bonds.
Oxygen atoms form two bonds. Halogens form one bond when they are surrounding
atoms; fluorine is always a surrounding atom.
Example: Write a Lewis structure for CCI2F2, one of the
compounds responsible for the depletion of stratospheric ozone. step 2: A: [ 1 X C(4e-)] + [2 X F(7e-)] + [2 X CI(7e-)] = 32 valence eI: 4 bonding = 8 valence eS: 32 valence e - 8 valence e = 24 valence e-
Write the Lewis structure for methanol, (molecular
formula CH40), an industrial alcohol that is also being considered as a gasoline alternative.The answer:
Muatan Formal
Note:
Bila beberapa kemungkinan struktur Lewis dapat dibuat, maka struktur dengan muatan formal yang paling kecil dan paling stabil yang dipilih.
H2SO4
H3PO4
Task Write the most likely Lewis structure for
(a) POCI3 (b) C2H4 (c) ICl2(d) ClO3-