Question

Give one example of a compound having a linear molecular structure that has an overall dipole moment (is polar) and one example that does not have an overall dipole moment (is nonpolar). Do the same for molecules that have trigonal planar and tetrahedral molecular structures.

Short answer

Examples of polar and nonpolar molecules for each molecular structure are: Linear: - Polar: HCl (due to the electronegativity difference between H and Cl) - Nonpolar: N₂ (both N atoms have the same electronegativity) Trigonal Planar: - Polar: SO₂ (S atom bonded to two O atoms and a lone pair on the central S atom) - Nonpolar: BF₃ (B atom bonded to three F atoms with equal electronegativity) Tetrahedral: - Polar: CH₃Cl (C atom at the center, three H atoms and one Cl atom) - Nonpolar: CH₄ (C atom at the center, 4 H atoms with equal electronegativity)

Step-by-step solution

Linear Molecular Structure

Linear molecular structures consist of two atoms bonded linearly. For a linear molecule to be polar, there must be a difference in electronegativity between the two atoms. For a nonpolar linear molecule, the electronegativity difference should be minimal. Example of polar linear molecule: HCl The electronegativity difference between H and Cl atoms creates a dipole, making the HCl molecule polar. Example of nonpolar linear molecule: N₂ Both N atoms have the same electronegativity, so there is no dipole moment, making the N₂ molecule nonpolar.

Trigonal Planar Molecular Structure

Trigonal planar molecular structures consist of a central atom bonded to three other atoms in a flat, triangular arrangement. For a trigonal planar molecule to be polar, the outer atoms must have different electronegativities. For a nonpolar trigonal planar molecule, the outer atoms must have the same electronegativity. Example of polar trigonal planar molecule: SO₂ In SO₂, the S atom is bonded to two O atoms, but there is also a lone pair on the central S atom, this creates an uneven distribution of electron density, resulting in a polar molecule. Example of nonpolar trigonal planar molecule: BF₃ In BF₃, the B atom is bonded to three F atoms, which all have equal electronegativity, making the molecule nonpolar.

Tetrahedral Molecular Structure

Tetrahedral molecular structures consist of a central atom bonded to four other atoms in a tetrahedral arrangement. For a tetrahedral molecule to be polar, the outer atoms must have different electronegativities. For a nonpolar tetrahedral molecule, the outer atoms must have the same electronegativity. Example of polar tetrahedral molecule: CH₃Cl In CH₃Cl, the C atom takes the center position, while the other atoms containing 3 H atoms and 1 Cl atom are different, making the molecule polar. Example of nonpolar tetrahedral molecule: CH₄ In CH₄, the C atom takes the center position, while all 4 outer atoms are H atoms, making the molecule nonpolar due to the equal electronegativity.