Inorganic chemistry Flashcards
all types of quantum numbers
- principal (n): energy of orbital (2 in 2s1)
- Orbital (l): letter (s/p/d/f)
- Magnetic (m): direction of orbital (x/y/z)
- Spin (s): magnetic properties (the 2 in 3p2)
structure of sigma bond
overlapping of s orbitals along the plane of the cell nuclei –> cylindrically symmetrical
bonding vs antiboding
bonding: low energy, orbitals overlap in phase and inteact constructively –> both orbitals have the same sign
antibonding: high energy, orbitals overlap out of phase and inteact destructively
!!only if there are more electrons in the bonding than antibonding MOs will there be bonding between two atoms
structure of a pi bond
overlap of p orbitals but no longer cylindrically symmetrical along intrernuclear axis (hence not as strong as sigma bond)
hybridisation definition
Redistribution of the energy of orbitals of individual atoms to give orbitals of equivalent energy
sp hybridisation
-linear molecules with 180 bond angle
-involved mixing of an s and p orbital
!! involved in compounds containing any carbon carbon triple bond
sp2 hybridisation
-trigonal molecules with a bond angle 120
-involves mixing one s and two p orbitals
!! involved in compounds containing any carbon carbon double bond
sp3 hybridisation
-tetrahedral molecules with a bond angle 109.5
-involves mixing one s and three p orbitals
!! involved in compounds containing any carbon carbon single bond
hybridisation of N atoms
- Undergo either sp/sp2/sp3 hybridisation
- follows same pattern as carbon atoms in terms of bonds and hybrids
!! lone pair of electron is present in the case of sp3 hybridisation –> shape is trigonal pyramidal but with 107 bond angle
hybridisation of O atoms
- Undergo either sp/sp2/sp3 hybridisation
- follows same pattern as carbon atoms in terms of bonds and hybrids
!! 2 lone pairs are formed during sp3 hybridisation –> molecule has a bent shape and a bond angle 104
electronegativity def
ability of an atom in a molecule to attract electrons to itself
trend of electronegativity
increases across period
decreases down a group
What causes the formation of polar bonds
a difference in electronegativity between two atoms (larger difference means a more polar bond)
!! electrons are pulled towards electronegative atom
What is an electrostatic potential map
shows distribution of charges over a molecule (electron density map)
Coordination number of a transition metal complex definition
the number of coordiate bonds between the ligand and the central metal ion
types of intermolecular forces
- london dispersion
- permanent dipole
- hydrogen bonding (NOF) - has a characteristic bond length around 0.177nm
- Ion-dipole forces (ions and water molecules in solution)
- Dipole - induced dipole (permanent dipole induces another temporary dipole)
what is the relationship between ion volume and hydrated ion volume
smaller ions have the largest volume when hydrated.
larger ions have the smallest volume when hydrated
3 types of thermodynamic systems
- OPEN: matter and energy can be exchanged with surroundings
- CLOSED: energy can be exchanged but not matter
- ISOLATED: neither energy nor matter can be exchanged
First law of thermodynamics
energy is conserved (any energy lost by system must be gained by surroundings and vice versa)
What is the internal energy of a system
Sum of all kinetic and potential energies of the components of the system
Equations used for change in internal energy
- ΔE = Efinal - Einitial,
ΔE > 0 the system has gained energy; ΔE < 0 the system has lost energy - ΔE=q+w , q = heat (q>0 heat is absorbed by the system), w = work (w>0 work is done on the system)
Enthalpy definition and equations
ENTHALPY: energy of a system at constant pressure
!! H=E+PV, E is the internal energy (ΔE = q + w), P in the pressure and V is the volume
State function definition
value of a state function is dependent only on the present state of a system and not the path the system took to reach that state
EG> internal energy, enthalpy, entropy, free gibbs energy
Standard enthalpy change for a reaction def
enthalpy change of reaction when all reactants and products are in their standard states
!! Hreaction = Hformation of products - Hformation of reactants
What is Hess’s law
if a reaction is carried out in a series of steps, deltaH for overall reaction is equal to the sum of enthalpy changes for all individual steps
What is the criteria for a spontaneous reaction
- ENTHAPLY CHANGE:
highly exothermic can indicate spontaneity but it doesnt have to be the case –> not definitive - ENTROPY: spontaneous reactions have a positive total entropy
- FREE GIBS ENERGY: spontaneous reactions have a negative deltaG (exergonic)
What has an entropy of 0
pure crystalline substances at absolute zero
Gibbs free energy definition
energy release by reaction that can be used to do work
- Under standard conditions:
DG 0 = enthalpy - (temp)(entropy) - Uner non standard conditions:
DG = DG 0 + RT ln Q
(where Q is the reaction quotient)
Colloids vs Suspensions vs Solutions
COLLOID: micro-heterogeneous mixture with larger particles (usually opaque). Particles cannot be filtered from its other components and do not settle out
SUSPENSION: heterogeneous mixture with large particles suspended in liquid. Particles do not dissolve in liquid (too large). Can be filtered away from liquid or separated using centrifugation
SOLUTION: homogeneous mixture (2+ substances), contain a solvent and solute, can be gaseous/liquid/solid
what factors affect whether a substance dissolves in another
- natural tendence od substances to mix and spread into larger volumes when not restrained
- Types of intermolecular forces:
-solute solute and solvent solvent interactions must absorb less energy that what is released by the formation of solute solvent interactions - Temperature and pressure
Dissolution vs Dissociation
DISSOLUTION: compound dissolving into solvent anf forming a solution
DISSOCIATION: ionic compound dissociating into its ions when added into solvent
What salts are always soluble
nitrate/ammonium and alkali metal salts