bonding and structure

• What is ionic bonding?

  • Involves oppositely charged ions
  • Held by strong electrostatic attractions
  • Example: Sodium and chlorine form ions
• What charge does sodium ion have?

  Positive (+1)
• Why does chlorine gain an electron?

  To achieve a full outer shell.
• What ions do group 1 elements form?

  1+ ions
• What ions do group 2 elements form?

  2+ ions
• Why is it easier for group 5 elements to gain 3 electrons than to lose 5?

  Because losing 5 electrons is more difficult than gaining 3.
• What is the charge of hydroxide ion?

  • 1
• What is the formula for nitrate ion?

  NO₃^-
• How do you determine the formula of ionic compounds?

  By using the swap and drop method.
• What is the formula for calcium nitrate?

  Ca(NO₃)₂
• What structure do ionic compounds like sodium chloride have?

  Giant ionic structures.
• Why do ionic compounds conduct electricity when molten or dissolved?

  Because the ions are free to move around.
• What is the melting point characteristic of ionic compounds?

  They have high melting points.
• What is covalent bonding?

  • Involves sharing of electrons
  • Electrostatic attraction between shared electrons and positive nuclei
  • Can form single, double, or triple bonds
• What is a dative covalent bond?

  It is where one atom donates both electrons to form a bond.
• How can a dative covalent bond be represented?

  Using an arrow in the displayed formula.
• What effect do lone pairs have on bond angles?

  Lone pairs repel more than bonding pairs, reducing bond angles.
• What is the bond angle in a tetrahedral molecule?

  109.5 degrees
• How does the presence of lone pairs affect the bond angle in water?

  It reduces the bond angle to 104.5 degrees.
• What are the shapes of molecules based on bond pairs and lone pairs?

  • Linear: 2 bond pairs, 180 degrees
  • Trigonal planar: 3 bond pairs, 120 degrees
  • Tetrahedral: 4 bond pairs, 109.5 degrees
  • Trigonal bipyramidal: 5 bond pairs, 90 and 120 degrees
  • Octahedral: 6 bond pairs, 90 degrees
• What is electronegativity?

  The ability of an atom to attract electrons in a covalent bond.
• How does electronegativity change in the periodic table?

  It increases as you move up and to the right.
• Which element is the most electronegative?

  Fluorine
• What is the trend of electronegativity in the periodic table?

  • Increases up a group
  • Increases across a period
  • Noble gases are excluded from this trend
• What happens to lone pairs in molecular geometry?

  Lone pairs can repel bond pairs, affecting the molecular shape.
• What is an example of a molecular shape with four bond pairs and two lone pairs?

  Square planar
• What is the bond angle in a square planar molecular shape?

  The bond angle is 90 degrees.
• How does electronegativity affect covalent bonds?

  Electronegativity is the ability of an atom to attract electrons in a covalent bond.
• What happens to the ionic character of a compound as the difference in electronegativity increases?

  The greater the difference, the more ionic the compound becomes.
• What is an example of a purely covalent molecule?

  Cl₂ (chlorine gas)
• What defines a polar covalent bond?

  A polar covalent bond occurs when there is a difference in electronegativity between the atoms.
• How does the charge distribution in a polar bond differ from a nonpolar bond?

  In a polar bond, electrons are unevenly distributed, while in a nonpolar bond, they are evenly distributed.
• Why are hydrocarbons considered nonpolar?

  The electronegativity difference between carbon and hydrogen is very small.
• What type of intermolecular force is also known as London forces?

  Induced dipole-dipole forces
• What causes induced dipole-dipole forces to occur?

  They occur when electrons shift in response to nearby molecules, creating temporary dipoles.
• How do induced dipole-dipole forces affect the boiling point of iodine?

  They contribute to the relatively low boiling point due to weak interactions.
• What happens to intermolecular forces when a liquid is boiled?

  Weak intermolecular forces are broken, allowing molecules to escape into the gas phase.
• What effect does branching have on the boiling point of hydrocarbons?

  Branching lowers the boiling point due to reduced surface contact.
• What defines permanent dipole-dipole forces?

  They occur between molecules that have a permanent dipole due to differences in electronegativity.
• How can you test if a molecule is polar using a charged rod?

  The polar molecule will bend towards the charged rod due to alignment of dipoles.