DM 1 + 2

Question 1

Why can you discuss the d-block as a collection of elements?

Answer 1

differences between elements are less sharp than those in the s-block + p-block
similarities across period = greater

Question 2

argon electronic configuration?

Answer 2

1s2 2s2 2p6 3s2 3p6

Question 3

Across the first row of d-block (scandium-zinc) each element has…..

Answer 3

• one more proton in nucleus + electron than the previous element
• electron enters 3d shell

(4s already filled first)

Question 4

What 2 elements don’t fit the the 3d pattern?

Answer 4

chromium + copper

Question 5

why are chromium + copper different?

Answer 5

• ground state = electrons arranged to give lowest total energy
• -ve charged electrons = repel eachother –> lower energy with electrons singly than paired in orbital
• 3d + 4s energy = close in period 4
• Cr + Cu = removing 4s electron into 3d = lower energy arrangement
• Cr = avoids having pair of electrons in same orital

Question 6

Ion formation of transition metals lose ______ first

Answer 6

4s

Question 7

Definition of a transition metal.

Answer 7

Transition metals form 1 or more
STABLE ions with
INCOMPETELY filled d-orbitals

Question 8

Why are ZINC and SCANDIUM not considered transition metals?

but are d-block elements

Answer 8

• zinc forms Zn+2 ion = 3d10
• -> full d-orbital
• scandium forms Sc+3 ion = 3p6
• -> empty d-orbital

Question 9

Why does copper form Cu+1

Answer 9

electronic cnfiguration of Cr + Cu = d5 + d10
= very stable

Cu+1 forms [Ar]3d10

Question 10

Why is Fe3+ more stable than Fe2+?

Answer 10

Fe3+ = [Ar]3d5

Fe2+ = [Ar]3d6

Question 11

finding % iron in iron ore

• iron + potassium manganate

Answer 11

• write eq
• moles MnO4- + Fe2+
• conc. Fe2+ (original sol.)
• % iron

Question 12

definition of catalyst

Answer 12

alters RATE of chemical reation without being USED UP in the process

offers an alternative reaction pathway that has lower AE than uncatalysed reaction

Question 13

definition of HETEROGENEOUS catalyst

Answer 13

catalyst different phase from reactants

usually solid metal catalyst + gas/liq reactants

Question 14

How can transition metals act as heterogeneous catalysts?

Answer 14

• use 3d + 4s electrons on metal surface –> form weak bonds to reactants
  = CHEMISORPTION
• once reation occured on surface these bonds can break + release product

Question 15

definition of homogeneous catalysis

Answer 15

catalyst = same phase as reactants

transition metals
usually aq + aq transition metal ion catalyst

Question 16

homogeneous catalysis usually involves the transition metal forming an…..

Answer 16

INTERMEDIATE compound
with 1 or more reactants
which then breaks down = products

Question 17

why are transition metals effective catalysts in REDOX reations

Answer 17

they can move from one OXIDATION STATE to the other

• Co moves between +2 and +3 states