properties Flashcards
define transition element
a d-block element which forms 1 or more stable ions with an incomplete d sub-shell
define d-block element
an element with its outermost electrons occupying the d subshell
electronic configuration for Ti
[Ar] 4s2 3d2
electronic configuration for V
[Ar] 4s2 3d3
electronic configuration for Cr
[Ar] 4s1 3d5
forms a half filled d subshell for stability
electronic configuration for Mn
[Ar] 4s2 3d4
electronic configuration for Fe
[Ar] 4s2 3d6
electronic configuration for Co
[Ar] 4s2 3d7
electronic configuration for Ni
[Ar] 4s2 3d8
electronic configuration for Cu
[Ar] 4s1 3d10
forms a full d subshell first for stability
why are Sc and Zn d-block elemnst but not transition elements?
Sc forms 3+ ions - empty d subshell
Zn forms 2+ ions - full d subshell
what are some physical properties of transition metals?
- form giant metallic lattices
- high density
- shiny
- good conductors of electricity
- high mp + bp
what are 3 properties of transition metals?
- variable oxidation states
- form coloured compounds due to partially filled d -orbitals
- good catalysts
why
why are transition metals good catalysts?
- provide a surface for reaction to take place
- transition metlas can change oxidation states by gaining or losing electrons so can form intermediates with the reactants to give a lower activation energy pathway
what is the catalyst used in the hydrogenation of alkenes
Nickel catalyst
C2H4 + H2 –> C2H6
- lowers temperature and pressure
