4) Unit 1 - Transition Metals Flashcards
if oxidation number increases this is known as _______.
if oxidation number decreases this is known as ________.
if oxidation number increases this is known as oxidation.
if oxidation number decreases this is known as reduction.
when writing orbitals box notations what rule must be followed for transition metals
electrons fill the 4s, and are lost from 4s, before 3d
‘electrons fill the 4s, and are lost from 4s, before 3d’
what 2 transition metals do not follow this rule and why
chromium and copper
they have half shell or full shell stability if an electron is moved from 4s to to 3d.
transition metals can act as catalyst and have colour because of what characteristic
their partially filled 3d orbital
why do scandium3+ and zinc2+ not behave as trantion metals
don’t have partially filled 3d orbital
what does a catalyst do
speeds up a reaction by allowing it to go in a path of lower activation energy
there are 2 ways in which transition metals act as catalyst.
Describe these 2 mechanisms.
coming soon
what are ligands
electron donors, which are usually negative ions or molecules with 1 or more lone pairs
what happens when a ligand surrounds a central transition metal
they form a transition metal complex, by forming a davtive covalent bond
ligands can be monodente, didente up to hexadente.
what does this mean
monodente - dontes one pair of lone pairs
didente - donates 2 pairs of lone pairs
etc..
what is the co-ordination number
number of bonds made by central transition metal
what are the 3 rules when naming transition metal complexes
1) Ligands in alphabetically order of name and not the prefix
2) Metal name and oxidation state of metal in brackets
3) if complex is overall negative then metal name ends in ‘ate’
3 Tips to use when writing transition metal complexes from their names
1) If the metal name ends in ‘ate’ we can expect the oxidation state of the complex to be negative
2) If its just the complex (no atom or ion outside the square bracket) then charge outside the bracket is the sum of all the oxidation sates within the square bracket
3) if it has an atom/ion outside the square bracket work out the overall charge of the complex (things in square bracket) and that will give an indication of how many atom/ion is needed
Describe how colour comes about in transition metals
- Light is absorbed when electrons in the lower energy level are promoted up to a d orbital of higher energy
- The wavelength of light absorbed to promote 1 electron up is what causes color, as its complementary color is seen
- e.g if 700nm (red) is needed to promote an electron up, green would be transmitted
The distance a 3d orbital is split is dependent on the ________.
Ligand
