Explanation:
There are 4 bonds between nonmetal atoms.
It is known that if ΔE (electronegativity difference between atoms that form the bond):
ΔE = 0 => non polar
0.4<ΔE<1.7 => polar
ΔE>1.7 => ionic
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Information needed:
The electronegativities of (please, the periodic table is useful here)
F = 3.98
Cl = 3.16
Br = 2.96
I = 2.66
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Procedure:
For F-F) ΔE = electronegativity (F) - electronegativity (F)
ΔE = 3.98 - 3.98 = 0 non polar
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For F-Cl) ΔE = 3.98 - 3.16 = 0.82
For F-Br) ΔE = 3.98 - 2.96 = 1.02
For F-I) ΔE = 3.98 - 2.66 = 1.32
Answer: F-I
