AQA A Level Chemistry: Bonding Flashcards
What is ionic bonding?
Ionic bonding is the electrostatic attraction between oppositely charged ions formed by the transfer of electrons from a metal to a non-metal.
What is a covalent bond?
A covalent bond is a shared pair of electrons between two non-metal atoms.
What is a dative covalent (coordinate) bond?
A dative covalent bond is a covalent bond where both electrons in the bond are donated by one atom.
What is metallic bonding?
Metallic bonding is the electrostatic attraction between positive metal ions and a sea of delocalized electrons.
Why do ionic compounds have high melting and boiling points?
Ionic compounds have strong electrostatic forces between oppositely charged ions, requiring a lot of energy to break these bonds.
Why do metals conduct electricity?
Metals conduct electricity because the delocalized electrons can move freely and carry a charge throughout the structure.
What is the shape and bond angle of methane (CH₄)?
Tetrahedral shape, 109.5° bond angle.
Q: What is the shape and bond angle of ammonia (NH₃)?
Trigonal pyramidal shape, 107° bond angle.
What is the shape and bond angle of water (H₂O)?
Bent (V-shaped) shape, 104.5° bond angle.
What is the shape and bond angle of carbon dioxide (CO₂)?
Linear shape, 180° bond angle.
What is electronegativity?
Electronegativity is the ability of an atom to attract a bonding pair of electrons in a covalent bond.
What is a polar bond?
A polar bond is a covalent bond where the electrons are unequally shared due to a difference in electronegativity.
What are Van der Waals forces?
Van der Waals forces are weak intermolecular forces caused by temporary dipoles in molecules.
What is a permanent dipole-dipole interaction?
Permanent dipole-dipole interactions occur between molecules with permanent dipoles due to differences in electronegativity.
What is hydrogen bonding?
Hydrogen bonding is a strong dipole-dipole interaction between a hydrogen atom bonded to N, O, or F and a lone pair on another electronegative atom.
Why does water have a high boiling point?
Water has strong hydrogen bonding between molecules, requiring more energy to overcome.
What is the trend in electronegativity across a period?
Electronegativity increases across a period due to increased nuclear charge and smaller atomic radius.
What is the trend in electronegativity down a group?
Electronegativity decreases down a group due to increased atomic radius and more electron shielding.
Why does ice have a lower density than water?
In ice, hydrogen bonds hold water molecules in an open lattice, creating spaces that make ice less dense.
Why are ionic compounds soluble in water?
Water molecules are polar and surround the ions, separating and dissolving them through ion-dipole interactions.
What is bond enthalpy?
Bond enthalpy is the energy required to break one mole of a bond in gaseous molecules.
Why do covalent substances not conduct electricity?
Covalent substances do not have free ions or electrons to carry a charge.
What is the difference between sigma and pi bonds?
Sigma bonds are formed by head-on overlap of orbitals, while pi bonds are formed by sideways overlap of p-orbitals.
Why do simple covalent molecules have low melting points?
Simple covalent molecules have weak intermolecular forces that require little energy to overcome.
What is the shape and bond angle of BF₃?
Trigonal planar shape, 120° bond angle.
