Define an atomic orbital
A region around the nucleus that can hold up to 2 electrons with opposite spins.
Define ionic bonding
Electrostatic attraction between positive and negative ions.
State the properties of an ionic compound
- forms giant ionic lattice
- high b + mp to overcome electrostatic attraction between ions.
- does not conduct electricity in the solid state as no mobile charge carriers.
Define a covalent bond
The strong electrostatic attraction between a shared pair of electrons and the nuclei of bonded atoms. (forms a molecule)
Define a dative bond
A covalent bond where shared pairs of electrons are supplied by one of the bonding atoms only.
What is VESPR theory?
Lone pairs repel more strongly than bond pairs
State the 6 shapes you MUST recall and their angles
non-linear (104.5), linear (180), pyrimdal (107), tetrahedral (109.5), trigonal planar (120), octahedral (90)
Define electronegativity
The attraction of a bonded atom for the pair of electrons in a covalent bond
Where do permanent dipoles exist?
In polarised bonds (unequal charges) like HCl
Explain why CO2 is NOT a polar molecule.
- Two C=O bonds have a permanent dipole
- They act in opposite directions and oppose
- Over the whole molecule, the dipoles cancel out
Define intermolecular forces
The weak interactions between dipoles of DIFFERENT molecules
Describe the strength of London forces
larger induced dipoles leads to greater london forces so there is a stronger attractive force between molecules
Explain the change in boiling points of NOBLE GASES.
Larger number of electrons, so larger induced dipoles, so more energy is required to overcome the intermolecular forces of attraction.
Define a simple molecular compound
Made up of simple molecules with a definite number molecular formula
Describe the properties of a simple molecule
- molecules held together with weak intermolecular forces
- atoms bonded together by covalent bonds
- Low m and bp (COVALENT BONDS DON’T BREAK.)
Describe the properties of water
- Solid ice is less dense than water (H-bonds hold water molecules further apart in open lattice in ice than water)
-high mp and bp (London forces and hydrogen bonding)
What are the properties of d-block metals?
high mp and bp, shiny appearance, conductors of electricity and heat
Define a transition element
D-block elements that form at least 1 ion with a partially filled d orbital
What are the properties of transition elements?
elements and compounds can act as catalysts
Form compounds with different oxidation states
Form coloured compounds
Define a complex ion
One or more molecules or negatively charged ions (ligands) bond to a central metal ion.
Define a ligand
A molecule or ion that donates a pair of electrons to a central metal ion to form a coordinate bond.
What is the coordination number?
The number of coordinate bonds attatched to the central metal ion
Describe the shape and penultimate structure of complex ions
coordination number of 6 - octahedral
coordination number of 4- tetrahedral
coordination number of 4 - platinum ONLY forms square planar
What type of isomerism do complex ions exhibit?
Cis-trans in square planar and octahedral, optical in octahedral complexes with only 2 or more bidentate ligands
