Suppose a large atom bonds with a small
atom. predict whether the properties of the new molecule
will be the same as the large atom, the same as the
small atom, or different from both atoms.

A large atom means that the radius would be large, meaning that the effective nuclear charge is low, therefore a lower electronegativity based on the periodic table. A smaller atom would mean the opposite, therefore a higher electronegativity. This combination would mean that the new molecule is polar.

Also, to answer your question, it would be most likely different from both atoms, as size doesn't really matter in a compound's properties.

False because saturated fatty acids contain only single bond