To determine which pair of elements would likely form the least polar bonds with each other, we need to consider the difference in electronegativity between each pair.
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Bromine and Nitrogen:
- Bromine (2.8) and Nitrogen (3.0)
- Difference = |3.0 - 2.8| = 0.2
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Oxygen and Phosphorus:
- Oxygen (3.5) and Phosphorus (2.1)
- Difference = |3.5 - 2.1| = 1.4
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Phosphorus and Bromine:
- Phosphorus (2.1) and Bromine (2.8)
- Difference = |2.8 - 2.1| = 0.7
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Nitrogen and Oxygen:
- Nitrogen (3.0) and Oxygen (3.5)
- Difference = |3.5 - 3.0| = 0.5
The smaller the difference in electronegativity, the less polar the bond will be.
From the calculations, the pair with the least difference in electronegativity is bromine and nitrogen (0.2).
Therefore, the answer is bromine and nitrogen.