Bonding Flashcards
Ionic bonding
Involves electrostatic attraction between oppositely charged ions in a lattice
Formula of sulfate ion
SO4^2-
Formula of hydroxide ion
OH-
Formula of nitrate ion
NO3^2-
Carbonate ion formula
CO3^2-
Ammonium ion formula
NH4+
Single Covalent bond vs multiple bonds
A single covalent bond contains a shared pair of electrons. Multiple bonds contain multiple pairs of electrons.
Co-ordinate bond (dative covalent)
A co-ordinate bond contains a shared pair of electrons with both electrons supplied by one atom.
Metallic bonding
Involves attraction between delocalised electrons and positive ions arranged in a lattice
What are the four types of crystal structure?
Ionic, metallic, macromolecular (giant covalent), molecular
Explain the energy changes associated with changes of state
SOLID —> MELTING = the particles vibrate and gain kinetic energy and the temp rises
MELTING —> LIQUID = all the energy goes into breaking bonds - there is no increase in kinetic energy or temperature
LIQUID —> BOILING = particles moving around, gaining kinetic energy
BOILING —> GAS = bonds are breaking, no increase in kinetic energy or temperature
BOILING —> GAS = particles moving around rapidly & increasing kinetic energy
Which repulsion is greater: lone-pair lone-pair, lone-pair bond-pair, bond-pair bond-pair?
BP-BP < LP-BP < LP-LP
What is the effect of electron pair repulsion on bond angles?
The greater the repulsion force between two pairs of electrons, the more far apart the two pairs of electrons will be and hence the larger the bond angle between them.
Electronegativity
The power of an atom to attract the pair of electrons in a covalent bond.
Explain why some molecules with polar bonds do not have a permanent dipole
Explain the electron distribution in a covalent bond between elements with different electronegativities
The electron distribution in a covalent bond between elements with different electronegativities will be UNSYMMETRICAL. This produces a polar covalent bond, and may cause a molecule to have a permanent dipole.
Name three forces between molecules
- permanent dipole-dipole forces
-induced dipole-dipole (van der Waals, dispersion, London) forces
-hydrogen bonding
The MP and BP of these molecular substances are influenced by the strength of these IMFs.
What is the importance of Hydrogen bonding in the low density of ice?
When water freezes, the water molecules are no longer free to move about and and the hydrogen bonds hold the molecules in fixed positions. In order to fit into this structure, the molecules are slightly less closely packed than in liquid water. This means ice is less dense than water.
How do lone pairs affect bond angles?
Lone pairs are more repulsive than bonding pairs as a result of being closer to the nucleus of the atom. This distorts the basic shape and reduces the bond angle by 2.5 degrees
Importance of hydrogen bonding in the anomalous boiling points of compounds
The boiling points of NH3, H2O and HF are all higher than those of the hydrides of the other elements in their group. This is because hydrogen bonding is present in NH3, H2O and HF, and it is stronger than dipole-dipole forces.
Examples of ionic crystal structures
