Hydrogen bonding occurs in H2O due to the presence of highly electronegative oxygen atoms bonded to hydrogen, creating strong dipole interactions.

C2 has a triple bond between the two carbon atoms, resulting in the shortest bond length compared to the others.

The bond angle in water is approximately 104.5 degrees due to the repulsion of the two lone pairs.

Bond order = (number of bonding electrons - number of antibonding electrons) / 2. For 10 electrons, if all are bonding, bond order = 10/2 = 5. If 2 are antibonding, bond order = (10-2)/2 = 4. The most stable configuration gives a bond order of 2.

The electron geometry for a molecule with four electron groups is tetrahedral, as the groups will arrange themselves to minimize repulsion.

SF6 has an octahedral geometry due to six bonding pairs of electrons around the central sulfur atom, with bond angles of 90 degrees.

SF6 has six bonding pairs and no lone pairs, resulting in an octahedral molecular geometry.

VSEPR theory states that the shape of a molecule is determined by the repulsion between electron pairs, including both bonding and lone pairs.

In methane, the carbon atom undergoes sp3 hybridization, forming four equivalent sp3 hybrid orbitals that arrange tetrahedrally.

A tetrahedral electron geometry with one lone pair results in a trigonal pyramidal molecular shape.

Phosphorus can form an expanded octet because it has available d orbitals to accommodate more than eight electrons in its valence shell.

CO2 has a linear geometry due to its two double bonds and no lone pairs on the central atom, resulting in a bond angle of 180 degrees.

Resonance structures differ only in the arrangement of electrons, while the positions of the nuclei remain the same, contributing to the overall hybrid structure.