d-block - characteristics Flashcards
(10 cards)
what is the difference between d-block elements and transition metals
d-block elements are all elements that have their valence electrons in d-orbitals
transition metals must also exhibit multiple oxidation states, some with partially filled d-orbitals
why are group 12 elements often not transition metals?
most only form compounds with fully filled d-orbitals
give 1 application of transition metals
catalysis of reactions that we depend on e.g. haber process, biological nitrogen fixation
primary valency definition
oxidation state, a value that never changes but some elements could have more than 1 value
- this is dictated by -ve ions
secondary valency definition
coordination number, the number of groups covalently bonded to a metal centre
- determined by both -ve/+ve
secondary valencies are directed to fixed positions in space about central ion
what type of compound do transition metals normally adopt?
commonly form coordination complexes, octahedral structures are most common
oxidation state definition
charge on central atom within a metal complex left if all ligands are removed, including electron pairs shared with central atoms
- formally oxidation state is meaningless, no physical reality, only served to keep track of what happens to electrons
how are d-block metal orbitals filled in complexes?
orbitals are filled in hydrogen order - all orbitals of a principle QN must be filled before moving up to the next one - forget 4s orbital first thing for all energy levels above as well
how does oxidation state of transition metals change periodically (L->R) ?
group oxidation state becomes increasingly less favoured as effective nuclear charge increases therefore ionisation energy increases
how does oxidation state of transition metals change as you go down the group?
group oxidation state is increasingly favoured, as rdf is more diffuse so less electron electron interactions, so electron loss / oxidation of metal is easier
