Does molecular shape change if outer atoms were not identical

We assumed that all of the outer atoms (atoms bonded to the central atom) were identical. Would the molecular shape/geometry change if they were not identical? Think about methane and chloromethane. Explain your answer using these examples.

I'm not sure how to use those examples within my answer...

First of all, all electrons are identical, though they may have different energies. The molecular shape/geometry is determined by the types of atomic orbitals that take part in bonding between atoms. For example, in methane, the C atom's 2s and three of the 2p orbitals mix together (hybridisation) to produce four identical sp3 orbits, which then combines with 1s orbit of hydrogen atoms. The resulting four sp3 orbits repel each other to give a tetrahedral shape of the methane molecule. The H-C-H bond angles are roughly 109.5 degrees.
In chloromethane same thing happens, but instead of four hydrogen atoms, there are three hydrogen and one chlorine atoms. The chlorine atom is relatively large in comparison to hydrogen atom, and C-Cl bond is longer than C-H bond. Thus, the interaction between C-Cl bonding electrons and C-H bonding electrons will be less causing the H-C-H bond angle to increase somewhat to about 110 degrees and Cl-C-H bond angle to decrease somewhat by similar amount to about 109 degrees.
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