5.3.1 transition metals Flashcards
what do transition metals have that makes them transition metals
incomplete d subshells
why is Zn not a transition metal
it can only form a 2+ ion where the d orbitals are complete
what are chemical properties of transition metals
forms a complex
forms coloured compounds
variable oxidation state
catalytic activity
what are physical properties of transition metals
high density
high melting and boiling point
good conductors
what is a complex
a central metal ion surrounded by ligands
what is a ligand
an atom, ion or molecule which can donate an electron pair
give two properties a cation must have to form a complex ion
high charge density to attract electrons
empty orbitals to accept lone pairs
what is a coordinate bond
when a shared pair of electrons in covalent bond come from only one of the bonding atoms
what ion forms linear complexes
Ag+
what ion forms square planar complexes
pt2+ Ni2+
what is a unidentate ligand
ligands which form one coordinate bond to a metal ion
what is a bidenate ligand
ligands which form two coordinate bonds to a metal ion
what is stereoisomerism
same structural formula but different 3D structure and
what is a multidentate ligand
ligands which form more than two coordinate bonds to a metal ion
what does haemoglobin contain
four Fe2+ centres which bond to oxygen and carry it around the blood
why are cn and co toxic
they are stronger ligands than oxygen so will bond to haemoglobin in preference
give the test for carbonate
- add any dilute acid and observe effervescence
* bubble gas through limewater co2 will turn it cloudy
give the test for sulphates
•add bacl2 and observe a white precipitate
test for halide ions
•add hno3 to remove carbon impurities •add agno3 and observe cl- white ppt br-cream ppt i-yellow ppt
give the test for ammonium
- add NaOH(aq) and heat
* NH4(g) would form which turns litmus paper from red to blue
give the colour change for positive ions when a hexa aqua complex forms a precipitate
cu2+: blue sol to blue ppt mn2+: pale pink sol to brown ppt fe2+: green sol to green ppt fe3+: yellow/brown sol to brown ppt cr3+: green sol to green ppt
name the metal ion that reacts with excess oh- and describe what happens
cr hydroxide dissolves and becomes cr(oh)6 green sol
