Module 5- transition elements Flashcards
Where are electrons from the d block elements in the top row lost from first (orbital)
4S fills first and is lost first in most cases
Which two d block elements have electron shell filling anomalies and why??
chronium and copper, an electron from the 4s pair moves into the 3d sub shell to fill the each orbital with one electron in cronium, and a pair of electrons in all 5 orbitals of the 3d subshell
Definition of a transition metal?
A transition metal is one which forms one or more stable ions which have incompletely filled d orbitals
which d block elements in the top row are and aren’t transition metals??
between Ti and copper you have transition elements, excluding Zinc because zinc only forms Zn2+, which has a complete d subshell, and Sc is also not a transition elements because it only forms Sc 3+ which has no electrons in the 3d sub shell
What is the electron configuration of Ni and Cu?
Use [Ar] to represent 1s to 3p orbitals
Ni= [Ar]3d8 4s2
Cu=[Ar] 3d10 4s1
what is the electron configuration of V and chromium?
V= [Ar] 3d3 4s2 Cr= [Ar] 3d5 4s1
3 properties of transition elements
- shiny in appearance
- high melting and boiling points
- conduct both heat and electricity
why do zinc compounds dissolve in water to form colourless solutions
Because zinc is not a transition metal so doesn’t have an incomplete d orbital, meaning there is no variation in colour, zinc forms 3+ ions with a full 3d sub shell, so doesn’t have a colour associated with it.
What colour is chromium ions in Cr2O7- (oxidation state of 6+) and then as a Cr3+ ion, and how does this explain why tertiary alcohols with acidified potassium dichromate stay orange, whilst primary and secondary alcohols go green??
Cr2O7- is orange in colour, whilst Cr3+ is green in colour. During the oxidation of alcohols using acidified potassium dichromate, primary and secondary can be oxidised, which allows the chromium to change oxidation state from +6 to +3 (be reduced), turning the solution from orange to green. Tertiary alcohols can’t be oxidised, so the solution stays orange in colour as the dichromate ion remains.
Whats the difference between a homogenous and heterogenous catalyst?
Homogenous catalysts are in the same state as the regents they are catalysing, whereas heterogenous are in a different state eg holiday catalysing a liquid.
Why do transitions elements in aqueous solution form coloured solutions
The colour of the ion of the transition elements is dictated by the incomplete d orbital, so they form different colours
What catalysts are used in the haber process and the hydrogenation of an alkene
Iron catalyst used in haber process
Nickel catalyst in hydrogenation
