Fluorine is much more electronegative than both silicon and sulfur, yet $\text{SF}_4$ has an overall dipole whereas $\text{SiF}_4$ does not. Suggest a reason for this difference.
Predict whether each of the following molecules will or will not have an overall dipole. Put a tick in the appropriate column for $\text{BCl}_3$, $\text{PCl}_3$, $\text{CCl}_4$ and $\text{SF}_6$.
Boron and silicon are two elements next to carbon in the periodic table. $\text{CCl}_4$ does not react with water, but $\text{BCl}_3$ and $\text{SiCl}_4$ do.
Suggest a reason for this difference in reactivity.
Construct equations to show the reaction of these two chlorides with excess water, for $\text{BCl}_3$ and for $\text{SiCl}_4$.
When $\text{SiCl}_4$ reacts with a small quantity of water, it forms an oxychloride $X$, $\text{Si}_2\text{Cl}_6\text{O}$. The mass spectrum of $X$ contains peaks at mass numbers of $133$, $149$, $247$, $263$ and $396$. (Assume that the species giving all of these peaks contain only the $^{16}\text{O}$, $^{35}\text{Cl}$ and $^{28}\text{Si}$ isotopes.)
Use these data to deduce the molecular formula of $X$.
Suggest the structures of the fragments responsible for the peaks at the following mass numbers: $133$, $247$ and $263$.
Hence suggest the displayed formula for $X$.