PROPERTIES OF MOLECULES BASED ON ITS POLARITY

• Intermolecular forces - influence the boiling point, melting point, and solubility of substances.
• In NH3, nitrogen has a lone pair of electrons in addition to forming bonds with three hydrogen atoms. This lone pair creates an uneven distribution of charge within the molecule, resulting in a net dipole moment and making NH3 a polar molecule.
• CO2 is non-polar because it has a symmetrical linear molecular geometry. Although the carbon- oxygen bonds are polar due to the difference in electronegativity between carbon and oxygen, the molecule is non-polar overall because the bond dipoles cancel each other out.
• Water (H2O) is a polar molecule because the oxygen atom is significantly more electronegative than the hydrogen atoms, resulting in an unequal sharing of electrons.
• The polarity of a molecule is determined primarily by the electronegativity difference between the atoms within the molecule and the molecular geometry.
• Water (H2O) is a polar molecule primarily because oxygen is more electronegative than hydrogen. This means that oxygen attracts the shared electrons in the covalent bonds more strongly than hydrogen does.
• In ammonia (NH3), the central atom is nitrogen (N). To determine the hybridization of the central nitrogen atom in ammonia, we first need to identify the number of electron domains around the nitrogen atom.
• CO2 is non-polar because it has a symmetrical linear molecular geometry.
• Oil molecules, typically composed of hydrocarbons, are non-polar Water molecules, on the other hand, are polar due to the electronegativity difference between oxygen and hydrogen atoms.
• The reason alcohol and water are miscible with each other is primarily due to the presence of polar characteristics in both molecules.
• Oil molecules have strong intermolecular forces, preventing them from mixing with the polar acetone molecules.
• Strong intermolecular forces - increase solubility.
• Polar molecules - tend to dissolve better in polar solvents.
• Increases solubility - The presence of hydrogen bonding affects the solubility of a substance in water.
• Salt and water - When salt is dissolved in water, it dissociates into its constituent ions (Na+ and Cl-) due to the attraction of water molecules to these charged ions. Salt dissociates into ions that interact with polar water molecules.
• Surface tension - is a measure of the cohesive forces between molecules at the surface of a liquid.
• Ion-dipole

  ➢ interactions occur between an ion (either a cation with a positive charge or an anion with a negative charge) and a polar molecule.

  ➢ Interactions between a polar molecule and an ion
• Dipole-dipole

  • Intermolecular forces arise from the interaction between permanent dipoles present in polar molecules.
  • These forces occur when the positive end of one polar molecule interacts with the negative end of another polar molecule, resulting in attractions between them.
• Dipole-induced dipole interactions occur between a polar molecule and a nonpolar molecule. The polar molecule induces a temporary dipole in the nonpolar molecule, resulting in an attractive force between them.
• Hydrogen bonding

  • Water (H2O) is a polar molecule due to the electronegativity difference between oxygen and hydrogen. Oxygen is more electronegative than hydrogen, causing the electrons in the O-H bonds.
  • The higher the electronegativity of the atom to which hydrogen is bonded, the stronger the hydrogen bonding will be.
  • Primarily responsible for the high surface tension of water.
• Nonpolar molecules - typically have weak intermolecular forces, Weak intermolecular forces result in lower boiling points, allowing these molecules to exist as gases at room temperature.
• The dipole moment of a molecule is a measure of the separation of positive and negative charges within it. A higher dipole moment indicates a greater degree of charge separation and thus a more polar molecule.
• LINEAR

  • CO2 has a linear molecular shape because it consists of two oxygen atoms bonded to a central carbon atom by double bonds.
  • Linear molecular geometry is the main factor contributing to CO2 being a non-polar molecule.
• TRIGONAL PYRAMIDAL -NH3 is trigonal pyramidal because the lone pair of electrons causes the bonding pairs to repel each other, resulting in a geometry where the three hydrogen atoms form a pyramid around the central nitrogen atom.
• OCTAHEDRAL - SF6 (sulfur hexafluoride) consists of one sulfur atom bonded to six fluorine atoms. The arrangement of these atoms results in an octahedral molecular shape around the sulfur atom.
• TRIGONAL PLANAR - BCl3, or boron trichloride, adopts a trigonal planar geometry. In this arrangement, boron is surrounded by three chlorine atoms, leading to a symmetric, planar shape with bond angles of approximately 120 degrees.
• TETRAHEDRAL

  • CH4, or methane, has a tetrahedral molecular shape. This means that the carbon atom at the center is bonded to four hydrogen atoms, arranged symmetrically around it in a three- dimensional structure.
  • Methane (CH4) is a non-polar molecule primarily due to its symmetrical tetrahedral shape.