Choose the ionic crystals ()
A. diamond
B. NaCl
C. Ice
D. SiC
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Choose the right name of 丙醛 and 环己酮 ()
A. Propanone and Cyclohexanal
B. Propanol and Cyclohexene
C. Propanal and Cyclohexanone
D. Propane and Cyclohexane
Choose the negative oxidation number ()
An element has lost electrons
B. An element is sharing electron with a less electronegative element
C. Free element
D. Cation
Choose the right characterizations of benzene () ①aliphatic ②C to C bond distances were identical ③aromatic ④delocalized unhybridized p orbital
A. ③④
B. ①②③
C. ①③
D. ②③④
Choose the right description ()
An element which obtains an electron possesses positive charge.
B. Silicon might take the place of carbon in forming long chains compounds.
C. Hydrogen is the lightest element.
D. Ozone is a typical nontoxic gas.
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