What is the molecular geometry if you have 4 single bonds around the carbon central atom?

Methylcyanoacrylate is the active ingredient in super glues. Its Lewis structure is (a) Give values for the three bond angles indicated. (b) Indicate the most polar bond in the molecule. (c) Circle the shortest carbon-oxygen bond. (d) Circle the shortest carbon-carbon bond.

Formamide, HC(O)NH2, is prepared at high pressures from carbon monoxide and ammonia, and serves as an industrial solvent (the parentheses around the O indicate that it is bonded only to the carbon atom and that the carbon atom is also bonded to the H and the N atoms). Two resonance forms (one with formal charges) can be written for formamide. Write both resonance structures, and predict the bond angles about the carbon and nitrogen atoms for each resonance form. Are they the same? Describe how the experimental determination of the HNH bond angle could be used to indicate which resonance form is more important.

Indicate which of the following molecules are polar. Draw the molecular structure of each polar molecule, including the arrows that indicate the bond dipoles and the molecular dipole moment. (a) HCN (b) I2 (c) NO