15 -Transition Metals Flashcards
whats a transition metal ? 1
An element which can form stable ions with an incompletely filled d subshell .
what’s a ligand ?1
particle with lone pair of electrons that bonds to central metal ion with dative covalent bond .
lewis acid ?
lone pair acceptor (central metal ion )
lewis base?
lone pair donor (ligand )
what shape complexes are Ag 2+ complexes ?1
coordination number ?
linear [Ag(NH3)2]2+ ====> tollens reagent
2
what’s coordination number ?1
number of coordinate bonds from ligands to metal ions .
Pt 2+ and Ni 2+ have a ————- shape and a coordinate number of ———-? 1
- square planar
- 4
Larger ligands such as cl-
- co-oridination number ?
- shape ?
- tetrahedral
- 4
Small complexes :
- co-oridnation number ?
- shape ?
- octahedral
- 6
unidentate ligand ?1
example ?
1 co-oridinate bond to a metal ion
exaamples :
cl- and OH- and CN- and H2O and NH3
Bidentate ligand ? 1
example ?
2 co-ordinate bonds to metal ion
examples :
1,2-diamineoethane and ethandioate ion (C2O4)2-
Multidentate ligand ? 1
examples :
2
what can you also call them C——?
more than 2 co-oridnate bonds to ligand
examples : EDTA4- AND Porphyrin
CHELATE ( greek word for claw ).
How do we get coloured ions?
4
1-3d orbital split when ligand comes to bond to them
2-The electrons tend to occupy the lower orbitals and energy is required to move the electron from a lower orbital to a higher one = corresponds to certain frequency of light = absorbed and the rest are transmitted( transmitted light is the colour)
How do we see the colour ? 1
1- the solution absorbs a frequency of light and a specific colour
2- the others are reflected back
3- the colour we see is the
How do we see the colour ? 3
1- the solution absorbs a frequency of light and a specific colour
2- the others are reflected back
3- the colour we see is the other frequencies COMBINED ==> COMPLEMENTARY COLOR
why is cu2+ BLUE and Zn 2+ colourless ? 2
1- Cu2 + is a transition metal whereas Zn 2+ is not
2- the Cu2+ has an incomplete d-subshell meaning that when it’s split the electron can be excited to a higher energy state and also fall back down= blue colour (complementary colour)
3- the Zn2+ = FULL 3d sub shell meaning it’s electrons don’t get excited and then jump down emitting a frequency of colour = colourless
Scandium and zinc aren’t transition metals because ——–?
- scandium has empty 3d shell sc3+
- zn has full 3d shell zn2+
how do you calculate the oxidation number of the metal ion in a complex? 1
total oxidation number - sum of charges of the ligands.
Ti ion colours
Ti3+
Ti2+
2
3+ ==> purple
2+ ===> violet
Vanadium ion colours ? 4 \+5 ==> VO2 1+ \+4 ==>VO2+ \+3 ==>V3+ \+2 ==>V2+
vo2 + = yellow (5)
vo2+ = blue (4)
V3+ = green (3)
v2+ = Violet (2)
chromium colours ? 2
Cr2O7 2- = +6
Cr3+ = 3+
dichromate is orange
cr3+ is green
Magnate colours ?3
MnO4- = + 7
MnO4-= +6
Mn2+ =+2
MnO4- = PURPLE
MnO4 2- = Green
Mn2+ = PALE PINK
iron colours : 2
Fe2+
Fe3+
Fe3+ = Yellow
Fe2+=Pale green
CO color = co2+
Nickel = Ni2+
Copper= Cu2+
Co2+ = pink Ni2+ = Green Cu2+ = pale blue
you can work out if a reaction is going to work based on electrode potentials ? 1
the E nought value should be positive for the reaction to occur . (+)
what does amphoteric mean ? 1
acts as acid and base
how does a catalyst work ? 4
1- gases are adsorbed onto the catalyst (covalent bonds are weakened )
2-they react and then desorb
3-the catalyst provides an alternative reaction pathway , hence lowers the activation energy
what happens in photochromic glasses in sunlight ? 2
CuCl + AgCl =====> CuCl2 +Ag
equation moves towards RHS in sunlight ,making silver .
