chem final

nuclear fission

the splitting of the nucleus which releases a huge amount of energy

nuclear fusion

the merging of two nuclei to make a larger nucleus; merging of small nuclei releases a huge amount of energy greater than fission

source of energy in nuclear reactions

strong nuclear force; when nuclei undergo fission or fusion some mass is lost (mass defect) and converted into binding energy as e=mc^2

nuclear reactions vs chemical reactions

nuclear reactions involve changes in nucleus not just electrons as some mass is lost (mass defect) and converted into huge amounts of energy through E=mc^2 while in chemical reactions the mass of the reactants and products stay the same and the energy changes are much smaller

weak field

don’t interact strongly with d-electrons in the metal ion; produce a smaller crystal field splitting of d electron energy states

why are strong field ligands more often diamagnetic

larger splitting value which favors electron pairing in the lower-energy t2g orbitals reducing the number of unpaired electrons

suggest a reason why Zn²+ ions are colorless

the 3d orbitals are filled so there can be no electronic transitions between the t and e levels so no light is absorbed producing colorless solutions

describe the changes that may take place in a compounds properties when weak field ligands are replaced by strong field ligands

because the splitting between the energies of the atomic orbitals increases, light absorption will occur at shorter wavelengths and the color of the complex will change

why is ___ a pi acid?

because it accepts electron density from the metal into its empty pi star antibonding orbitals, increasing ligand splitting

why __ a pi base?

can donate extra electron density into the metals t2g orbitals which increases the t2g energy, reducing splitting value making it weak field

why is (en, nh3) neither pi base or acid

only sigma bonds, donate electron density into the metal’s eg orbitals, no pi donation to to push energy up leading to larger splitting value and a stronger field

bonding

ligand is pi acid (empty pi star orbitals) so functions as pi acceptors

non-bonding

ligand only does sigma notation, t2g untouched

antibonding

ligand is a pi base (filled p orbitals), t2g set interacts with the filled p orbitals on the ligands

ligand field theory

pi donor

overlaps with metal t2g which raises t2g, raising t2g energy by donating electrons raising t2g energy narrowing the gap between t2g and eg (smaller splitting) leading to a weaker field

ligand field theory

pi acceptor

backhanding from t2g which lowers t2g energy as it pulls electrons from the metal’s t2g orbitals into their empty pi star orbitals lowering t2g energy widening the gap (larger splitting) leading to a stronger field

ligand field theory

sigma only

t2g mostly unchanged so nonbonding leading to moderate splitting