Prelim Flashcards
Aufbau Principle
The lowest energy levels are filled first and thus, provided the relative energies are known, the electron configuration can be deduced.
Pauli Exclusion Principle
No two electrons in the same atom can have the same set of 4 quantum numbers.
Hund’s Rule
When degenerate orbitals are available, electrons fill singly, keeping spins parallel before pairing starts.
The 4 quantum numbers
- Principle, angular, magnetic, spin
- n, l, ml, ms
How a line is produced in the emission spectrum
- The lines in the spectrum are produced when electrons are promoted to a higher energy level (by heat or electrical discharge)
- In falling back down the atom emits energy/ radiation of a specific wavelength or frequency. (The difference between the energy levels can be calculated)
Infrared Spectroscopy
- IR causes the molecules the vibrate, resulting in bending/ twisting/ rotating/ stretching.
- Atoms in the functional groups absorb at different wavelengths/frequencies/ wavenumbers/ energies
Mass Spectroscopy
- tiny samples of an unknown compound is injected and vaporised into the mass spec machine
- higher energy electrons bombard the compound with enough energy to knock the electron from molecules that are ionised and broken down into smaller fragments
What are ligands
Either negative or neutral molecules with at least one lone pair of electrons.
Valence Shell Electron Repulsion Theory
VSEPR is used to explain why molecules adopt a peculiar shape
Transition Metal
- A transition metal is one which forms one or more stable ions which have incompletely filled d orbitals.
- Properties: forms coloured compounds, variable oxidation states, forms complexes with ligands, show catalytic activity
Rate of reaction
The change in concentration of a reactant or the change in concentration of a product that occurs during a given period of time.
2nd Law of Thermodynamics
- In any spontaneous process, the overall degree of disorder (entropy) must always increase.
- For a reaction to be feasible, the total entropy change should for a reaction system and its surroundings must be positive.
3rd Law of Thermodynamics
At absolute zero a crystal lattice has perfect order and therefore zero entropy.
Monodentate ligands
Donates\ shares one lone\ non-bonded pair of electrons
Heating under reflux allows..
- To allow for prolonged heating
- To prevent reactant from escaping
Mixed melting point analysis
- Look up melting point of pure substance
- Link the melting point value to purity
Primary standard
- Substance to prepare solutions to a known concentration (standard solution)
- Note NaOH is not a primary standard
Criteria for primary standard
- Available pure
- Stable in air
- Readily soluble
- Give stable solution
What causes d orbital splitting
Repulsion from the lone pair of electrons from a ligand
How does an NMR work
- Hydrogen nuclei fall to the low energy/ align with magnetic field
- Different wavelengths emitted for different Hydrogen environments
Why different binds absorb different wave numbers of IR
- different atoms in bond
- different type of vibration/stretch
Definition of rate of reaction
Changes in the concentration of the reactant or product that occurs during a given period of time
Drugs definition
Substances which alter the biochemical processes in the body
Agonist definition
Mimics the body’s naturally active molecule so when bonded to the receptor site it produces the same responses as the body’s on molecule would do.
Antagonists definition
Bind strongly to the receptor site, blocking the body’s natural natural molecule from binding and preventing the triggering of the natural response.
Optical isomers
Non-superimposable mirror images of the molecule
Enantimers
Simple molecules which show optical isomerism as two isomers
