Draw a ‘dot-and-cross’ diagram to show how the outer electrons are arranged in one formula unit of $Mg_2Si$. Assume that magnesium silicide is ionic.
When solid $Mg_2Si$ is added to water, silane gas, $SiH_4$, and a solution of magnesium hydroxide are formed. Write the equation for this reaction. Include state symbols.
Suggest, with reference to structure and bonding, why $SiH_4$ exists as a gas at room temperature.
The table gives the electronegativity values of carbon, hydrogen and silicon. $C$-$H$ and $Si$-$H$ bonds have weak dipoles. Use the electronegativity values in the table to show the polarity of the $C$-$H$ and $Si$-$H$ bonds.
Explain why methane, $\text{CH}_4$, does not have an overall dipole moment.
$\text{SiH}_4 + 2\text{O}_2 \rightarrow \text{SiO}_2 + 2\text{H}_2\text{O}$ $\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$ Suggest, with reference to bond energies from the Data Booklet, why $\text{SiH}_4$ reacts in air without heating but $\text{CH}_4$ has to be ignited before combustion occurs.
Silicon dioxide reacts with hot, concentrated sodium hydroxide. Identify the two products formed in this reaction.
Describe how the silicon dioxide behaves during this reaction.