Answer:
The electron geometry, molecular geometry and idealized bond angles for these molecules respectively are:
a. CF4: tetrahedral, tetrahedral and 109.5 degrees
b. NF3 tetrahedral, trigonal pyramidal and 102.5 degrees
c. OF2 tetrahedral, angular and 103 degrees
d. H2S tetrahedral, angular and 92.1 degrees
Explanation:
The electron geometry considers the bound atoms and unbound electron pairs to determine the geometry. The four molecules have four bound atoms and/or unbound electrons pairs, thus they have a tetrahedral geometry. On the other hand, the molecular geometry only considers the position of bound atoms to determine the geometry.
Between H3O and H2O, H2O has a smaller bond angle due to the two unbound electron pairs. The bond angle decrease as the number of unbound electron pairs increases in every molecule.
CO2 and CCl4 are both nonpolar because of the 3D geometry of the molecule. Each individual bond is polar but both molecules have symmetrical geometry so the dipole bonds are canceled.
CH3F is a polar molecule because the dipole between the C-H and C-F bonds are differents thus, besides the symmetrical geometry the dipole bonds are not canceled.
Molecular geometry about the left carbon atom in CH₃CO₂CH₃ is tetrahedral.
The geometry around left carbon that is CH₃ is tetrahedral.
As the hybridization around left carbon is sp³ that shows its geometry should be tetrahedral and as there are 4 ligands around carbon and there is no lone pair present so the geometry is tetrahedral. So, the molecular geometry about the left carbon atom in CH₃CO₂CH₃ is tetrahedral.
Explanation:
Calcium chloride is an ionic compound as it is formed by transfer of an electron to each chlorine atom.
So, being an ionic compound calcium chloride is able to dissociate completely into water.
Hence, the dissociation reaction will be as follows.

Since, two electrons has been lost by single calcium atom. Therefore, calcium atom will have a charge of +2.
Thus, we can conclude that the charge on the calcium ion, in elementary units is +2.
If the bonds are held together tightly, as an ionic bond or even a covalent bond, there will need to be a strong force to separate those bonds. This would by why their would be a high melting point. Another reason would be re-activity. <span />