Determine whether each molecule is polar or nonpolar. b. SiCl4

Verified step by step guidance

1. Identify the central atom in the molecule. For SiCl₄, the central atom is Si (silicon).
2. Determine the number of valence electrons for the central atom. Silicon has 4 valence electrons.
3. Consider the surrounding atoms and their electronegativity. Chlorine (Cl) is more electronegative than silicon.
4. Examine the molecular geometry. SiCl₄ has a tetrahedral shape with bond angles of 109.5°.
5. Assess the symmetry of the molecule. In a tetrahedral molecule like SiCl₄, the symmetry causes the dipole moments to cancel out, making the molecule nonpolar.

Key Concepts

Molecular Polarity

Molecular polarity refers to the distribution of electrical charge across a molecule. A molecule is considered polar if it has a significant difference in electronegativity between its atoms, leading to an uneven distribution of charge. This results in a dipole moment, where one end of the molecule is slightly positive and the other is slightly negative.

Symmetry in Molecules

The symmetry of a molecule plays a crucial role in determining its polarity. If a molecule is symmetrical, the dipole moments of its bonds can cancel each other out, resulting in a nonpolar molecule. Conversely, asymmetrical molecules often have a net dipole moment, making them polar.

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electrons in a bond. In a molecule, differences in electronegativity between bonded atoms can lead to polar covalent bonds, where electrons are shared unequally. Understanding electronegativity helps predict the polarity of bonds and, consequently, the overall polarity of the molecule.