Analyze the bonds of ccl4. what is the shape of the ccl4 molecule? is it symmetrical? does this mean that the ccl4 molecule is polar or nonpolar?

C-Cl bond is polar.

As Cl is more electronegative than C,  

Cl pulls the shared electrons towards its side making the C-Cl bond polar.

Polar meaning C gets a partial positive charge and Cl gets a partial negative charge. Thus C-Cl bond becomes polar.

CCl4 molecule is tetrahedral.

And its shape is symmetrical.

That means its similar on all corners or all planes and it can be cut into equal halves from any plane.

C-Cl bond is polar.But the C-Cl polairty gets cancelled out as its pulled equally from all sides.

Since the molecule is symmetrical CCl4 is non polar.  

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.