C₂H₂
a. resonance
b. no resonance

no resonance

Explanation:

Since there is only one possible lewis structure C2H2 does not have resonance. A molecule has resonance if more than one lewis structure can be drawn for that molecule. For molecules with resonance, each lewis structure individually does not accurately depict the structure of the molecule

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer