1.4 - bonding

• What is an ionic bond?

  A bond formed by the electrical attraction between positive and negative ions.
• What is a covalent bond?

  A bond with a pair of electrons shared between two atoms with opposite spin.
• What is a coordinate bond?

  A covalent bond in which both shared electrons come from one atom.
• What is the significance of degrees in breaking bonds?

  Degrees may be necessary to break bonds in certain cases, such as in the Sun.
• What are giant molecules?

  Structures formed by millions of atoms bonded together, such as salt or diamond.
• What are the different types of chemical bonds?

  • Ionic bond
  • Covalent bond (including coordinate bond)
  • Metallic bond
• What is the basic cause of bonding in atoms?

  The electrostatic attractions between positively charged nuclei and negatively charged electrons outweigh the repulsions.
• How can bonds be represented visually?

  Bonds can be shown by dot and cross diagrams.
• What do 'dot and cross' diagrams represent?

  They show the outer electrons of one atom as dots and those of the other atom as crosses.
• What happens in ionic bonding?

  One atom gives one or more electrons to another atom, resulting in a cation and an anion that attract each other.
• How do covalent bonds form?

  Each atom gives one electron to form a bond pair with opposite spins.
• What is the difference in coordinate bonding?

  Both electrons in the bond pair come from the same atom.
• What is the role of attractive and repulsive forces in bonding?

  Attractive forces between protons and electrons outweigh repulsive forces.
• What happens if atoms get too close together?

  The nuclei and inner electrons repel those of the other atom, establishing a bond length.
• What is electronegativity?

  It is the ability of an atom to attract electrons in a covalent bond.
• What is the Pauling scale used for?

  To assign numerical values for electronegativity.
• What does a higher electronegativity value indicate?

  The element can attract bonding electrons more strongly.
• What creates polar bonds?

  A difference in electronegativities between bonded atoms leads to unequal sharing of electrons.
• When is a bond considered non-polar?

  When the atoms have equal electronegativities and share charges equally.
• What is the electronegativity difference for non-polar covalent bonds?

  Less than about 0.4.
• What is the electronegativity difference for polar covalent bonds?

  Between 0.4 and about 1.9.
• What is the electronegativity difference for ionic bonds?

  About 2.0 or more.
• How does electronegativity affect the polarity of bonds in methane (CH₄) and hydrogen fluoride (HF)?

  Methane has similar electronegativity values, making C–H bonds not highly polar, while HF has a more electronegative F, making the bond polar.
• What are the three types of intermolecular forces?

  • Dipole-dipole forces
  • Induced dipole-induced dipole forces
  • Hydrogen bonds
• What are dipole-dipole forces?

  Attractions between polar molecules due to their dipoles.
• What causes induced dipole-induced dipole forces?

  Temporary dipoles created by the motion of electrons around the nuclei.
• What is intermolecular bonding?

  Weak bonding that holds molecules together, governing the physical properties of substances.
• What is intramolecular bonding?

  Strong bonding between atoms in a molecule that governs its chemistry.
• What is the Van der Waals force?

  Intermolecular forces that include induced dipole-induced dipole forces.
• What is hydrogen bonding?

  Strong intermolecular forces between molecules containing H atoms bonded to highly electronegative elements (N, O, or F).
• How does the charge density of hydrogen affect hydrogen bonding?

  The high charge density of the bonded hydrogen atom allows for strong dipole-dipole attractions.
• How does the number of electrons in a molecule affect induced dipole-induced dipole forces?

  The strength of these forces increases with the number of electrons, leading to larger temporary dipoles.
• What is the relationship between induced dipole-induced dipole forces and boiling temperatures?

  Higher boiling temperatures in noble gases or halogens indicate stronger induced dipole-induced dipole forces.
• What are van der Waals forces?

  They are the combined effects of induced dipole-induced dipole forces and hydrogen bonds.
• How do hydrogen bonds form between molecules?

  They form when a δ+ hydrogen atom attracts a lone pair of electrons from a highly electronegative atom in another molecule.
• What is the significance of the high charge density of hydrogen in hydrogen bonding?

  It allows for strong dipole-dipole attractions between molecules.
• What happens to the strength of intermolecular forces as the number of electrons in a molecule increases?

  The strength of intermolecular forces increases.
• Why do larger molecules have stronger intermolecular forces?

  Because they have more electrons, leading to greater fluctuations in the electron cloud.
• What are the two types of intermolecular forces called?

  Van der Waals forces.
• What are hydrogen bonds?

  Special intermolecular forces between hydrogen atoms and highly electronegative elements like fluorine, oxygen, or nitrogen.