Which of the following pairs of atoms do not exhibit a covalent bond? cs and f o and o s and o p and cl

The answer is Cs and F. S and O  are both non-metals and if I am not mistaken they are both on the right side of the periodic table. S and O exhibit a covalent bond, the other pairs do too except for the first pair of atoms.  Therefore, the answer is  A. Cs and F.

The answer is solid copper 

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