Answer:
A molecule is tetrahedral if the central atom has four bonds and no lone pairs.
Explanation:
A typical example is a molecule of methane (see image).
The electron pairs in the bonds repel the electrons in the other bonds, so they all try to get as far from each other as possible.
They can do this if the bonds point to the corners of a tetrahedron, with bond angles of 109.5°.
Answer:
When two single single bonds separated by a double bond (e.g C=C-C=C or C=C-C=O in the case of 2-cyclohexenone), the effect of resonance among those there bonds will be observed.
Explanation:
Since the Oxygen atom has higher electronegativity, it will cause the electrons in the resonance bonds 'flow' toward the Oxygen atom, so that the C=C will 'lose' some electron. The signal read for that bond will be different from other alkene structure.
Attachment is the resonance structure of 2-cyclohexene.
