How many valid electron dot formulas—having the same number of electron pairs for a molecule or ion—can be written when a resonance structure occurs?

2 or more

Explanation:

There are 2 or more valid electron dot formulas—having the same number of electron pairs for a molecule or ion—can be written when a resonance structure occur as we know that Sharing of electrons takes place so that atoms achieve noble gas configurations. So, How is it that an electron dot arrangement reflects a covalent bond? An electron dot arrangement represents a pair of dots with the mutual electrons of a covalent bond.  A great energy of dissociation from bonds leads to a solid covalent bond.

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.