How can I determine hybridization of central atom?
There is a cheesy-easy way to determine hybridization on central atoms.
For CH4, the hybridization is sp3. How many electron domains (areas of electrons) are there around the central carbon? 4 and sp3 represents 4 hybridized orbitals.
For C2H2, acetylene, the hybridization is sp, representing 2 electron domains. Looking at this from one of the carbon's point of view, it has a triple bond with the other carbon (a triple bond represents ONE electron domain or area of electrons) and ONE bond with the hydrogen.
In SF6, there are 6 electron domains, thus the hybridization is sp3d2. Sometimes this is written d2sp3. 2 d's plus one s plus 3 p's = 6