Both a particle and a wave?
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.
A covalent bond? Not sure how much detail you want, sorry
1s22s22p63s23p64s23d104p5 is the answer
