Course Spec Stuff Flashcards
What is electronegativity ?
Electronegativity is a measure of the attraction an atom involved in a bond has for the electrons of the bond.
What is a first ionisation energy ?
The first ionisation energy is the energy required to remove one mole of electrons from one mole of gaseous atoms.
What is a covalent bond ?
In a covalent bond, atoms share pairs of electrons. The covalent bond is a result of two positive nuclei being held together by their common attraction for the shared pair of electrons.
How do polar covalent bonds arise ?
-Polar covalent bonds are formed when the attraction of the atoms for the pair of bonding electrons is different (different electronegativities).
-The shared bonding electrons are pulled closer towards the atom with a higher electronegativity, creating partial charges, which gives rise to a dipole.
-Delta positive (δ+) and delta negative (δ-) notation can be used to indicate the partial charges on atoms, which give rise to a dipole.
What are London Dispersion Forces ?
-They are formed as a result of electrostatic attraction between temporary dipoles and induced dipoles caused by movement of electrons in atoms and molecules.
-London dispersion forces are forces of attraction that can operate between all atoms and molecules.
-These forces are much weaker than all other types of bonding.
What is a permanent dipole - permanent dipole interaction ?
A permanent dipole - permanent diploe interaction is the electrostatic attraction between the oppositely charged dipole ends of two or more polar molecules.
How is a polar molecule formed ?
A polar molecule is formed if it has a permanent dipole and an asymmetrical spatial arrangement of polar covalent bonds.
How are hydrogen bonds formed ?
Hydrogen bonding is a very strong type of permanent dipole – permanent dipole interaction, occurring between molecules that have hydrogen bonded to a strongly electronegative element such as N, O or F, due to a large difference in electronegativity creating a highly polar bond that causes stronger intermolecular attractions.
When does a metal and a non-metal form a polar covalent bond ?
If the difference in electronegativities is less than two
What makes London Dispersion Forces Stronger
The bigger the atom due to an increase in total number of electrons, the greater the London forces due to larger dipoles formed.
