15 -Transition Metals

Question 1

whats a transition metal ? 1

Answer 1

An element which can form stable ions with an incompletely filled d subshell .

Question 2

what’s a ligand ?1

Answer 2

particle with lone pair of electrons that bonds to central metal ion with dative covalent bond .

Question 3

lewis acid ?

Answer 3

lone pair acceptor (central metal ion )

Question 4

lewis base?

Answer 4

lone pair donor (ligand )

Question 5

what shape complexes are Ag 2+ complexes ?1

coordination number ?

Answer 5

linear [Ag(NH3)2]2+ ====> tollens reagent

2

Question 6

what’s coordination number ?1

Answer 6

number of coordinate bonds from ligands to metal ions .

Question 7

Pt 2+ and Ni 2+ have a ————- shape and a coordinate number of ———-? 1

Answer 7

• square planar

- 4

Question 8

Larger ligands such as cl-

• co-oridination number ?
• shape ?

Answer 8

• tetrahedral

- 4

Question 9

Small complexes :

• co-oridnation number ?
• shape ?

Answer 9

• octahedral

- 6

Question 10

unidentate ligand ?1

example ?

Answer 10

1 co-oridinate bond to a metal ion
exaamples :
cl- and OH- and CN- and H2O and NH3

Question 11

Bidentate ligand ? 1

example ?

Answer 11

2 co-ordinate bonds to metal ion
examples :
1,2-diamineoethane and ethandioate ion (C2O4)2-

Question 12

Multidentate ligand ? 1
examples :
2
what can you also call them C——?

Answer 12

more than 2 co-oridnate bonds to ligand
examples : EDTA4- AND Porphyrin
CHELATE ( greek word for claw ).

Question 13

How do we get coloured ions?

4

Answer 13

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)

Question 14

How do we see the colour ? 1

Answer 14

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

Question 15

How do we see the colour ? 3

Answer 15

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

Question 16

why is cu2+ BLUE and Zn 2+ colourless ? 2

Answer 16

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

Question 17

Scandium and zinc aren’t transition metals because ——–?

Answer 17

• scandium has empty 3d shell sc3+

- zn has full 3d shell zn2+

Question 18

how do you calculate the oxidation number of the metal ion in a complex? 1

Answer 18

total oxidation number - sum of charges of the ligands.

Question 19

Ti ion colours
Ti3+
Ti2+
2

Answer 19

3+ ==> purple

2+ ===> violet

Question 20

Vanadium ion colours ? 4
\+5 ==> VO2 1+
\+4 ==>VO2+
\+3 ==>V3+
\+2 ==>V2+

Answer 20

vo2 + = yellow (5)
vo2+ = blue (4)
V3+ = green (3)
v2+ = Violet (2)

Question 21

chromium colours ? 2
Cr2O7 2- = +6
Cr3+ = 3+

Answer 21

dichromate is orange

cr3+ is green

Question 22

Magnate colours ?3
MnO4- = + 7
MnO4-= +6
Mn2+ =+2

Answer 22

MnO4- = PURPLE
MnO4 2- = Green
Mn2+ = PALE PINK

Question 23

iron colours : 2
Fe2+
Fe3+

Answer 23

Fe3+ = Yellow

Fe2+=Pale green

Question 24

CO color = co2+
Nickel = Ni2+
Copper= Cu2+

Answer 24

Co2+ = pink 
Ni2+ = Green
Cu2+ = pale blue

Question 25

you can work out if a reaction is going to work based on electrode potentials ? 1

Answer 25

the E nought value should be positive for the reaction to occur . (+)

Question 26

what does amphoteric mean ? 1

Answer 26

acts as acid and base

Question 27

how does a catalyst work ? 4

Answer 27

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

Question 28

what happens in photochromic glasses in sunlight ? 2

Answer 28

CuCl + AgCl =====> CuCl2 +Ag

equation moves towards RHS in sunlight ,making silver .