A  polar covalent bond is a covalent bond between different atoms that attract the shared electrons by different amounts and cause an imbalance of what ?
neutron distribution
proton distribution
ions distribution
electron distribution
EXAMPLE 13 Describe the bonding in the nitrite ion in terms of a combination of hybrid atomic orbitals and molecular orbitals. Lewis dot structures and the VSEPR model predict that the NO2− ion is bent. Given: chemical species and molecular geometry Asked for: bonding description using hybrid atomic orbitals and molecular orbitals Strategy: A Calculate the number of valence electrons in NO2−. From the structure, predict the type of atomic orbital hybridization in the ion. B Predict the number and type of molecular orbitals that form during bonding. Use valence electrons to fill these orbitals and then calculate the number of electrons that remain. C If there are unhybridized orbitals, place the remaining electrons in these orbitals in order of increasing energy. Calculate the bond order and describe the bonding. Solution: A The lone pair of electrons on nitrogen and a bent structure suggest that the bonding in NO 2− is similar to the bonding in ozone. This conclusion is supported by the fact that nitrite also contains 18 valence electrons (5 from N and 6 from each O, plus 1 for the −1 charge). The bent structure implies that the nitrogen is sp2 hybridized. B If we assume that the oxygen atoms are sp2 hybridized as well, then we can use twosp2 hybrid orbitals on each oxygen and one sp2 hybrid orbital on nitrogen to accommodate the five lone pairs of electrons. Two sp2 hybrid orbitals on nitrogen form σ bonds with the remaining sp2 hybrid orbital on each oxygen.