Question

which set of elements would make a polar covalent bond? (electronegativity chart) b and f cl and na o and i p and h

Explanation:

• For a polar covalent bond, the electronegativity difference ($\Delta EN$) between the two atoms should be in the range \(0.5\leq\Delta EN < 2.0\).
• For \(B\) (electronegativity \(EN = 2.0\)) and \(F\) (\(EN=4.0\)), \(\Delta EN=4.0 - 2.0=2.0\). This is the boundary for an ionic - polar covalent (some consider it ionic as per some textbooks, but if we strictly go by the range for polar covalent as \(0.5\leq\Delta EN<2.0\) in a simple - rule - based approach, we need to check others).
• For \(Cl\) (\(EN = 3.0\)) and \(Na\) (\(EN = 0.9\)), \(\Delta EN=3.0 - 0.9 = 2.1>2.0\), so it is an ionic bond.
• For \(O\) (\(EN=3.5\)) and \(I\) (\(EN = 2.5\)), \(\Delta EN=3.5 - 2.5=1.0\). Since \(0.5\leq1.0<2.0\), the bond between \(O\) and \(I\) is a polar covalent bond.
• For \(P\) (\(EN = 2.1\)) and \(H\) (\(EN=2.1\)), \(\Delta EN=2.1 - 2.1 = 0\), so it is a non - polar covalent bond.

Answer:

O and I