Ts Flashcards
What is a transition element
They are dblock elements which form one or more stable ions with an incomplete d subshell
Physical properties of transition metals
1 high melting point
2 high density
3 hard and rigid
4 good conductor of heat and electricity
Chemical properties of transition metals
Variable oxidation states
Behave as catalyst
Form complex ions
Form coloured cmpds
Why do transition elements have variable oxidation states
They can lose electrons from both 4s and 3d subshells due to the LITTLE ENERGY DIFFERENCE between these two subshells
Define the term transition metal complex
Consists of a central metal atom/ion surrounded by ligands via dative bonds
Why do transition elements form complex ions
They have vacant d orbitals that are energetically accessible
What is a ligand
A ligand is a species that has one or more lone pairs of electrons that form a dative bonf with a central metal atom
What is a polydentate ligands
Polydentate are ligands which form multiple dative bonds by donating more than 2 lone pairs of electrons to the central metal atom
What is coordination number
Number of coordinate bonds that are formed between the ligands and the central metal ion
What are degenerate d orbitals
They all have the same energy level
Explain why transition elements form coloured cmpds
- The degenerate d-orbitals are split into 2 sets of non-degenerate d-orbitals having different energies
- An electron from the lower set of d-orbitals is promoted to the higher set of d-orbitals
- A certain frequency of light is absorbed
- The observed colour is complimentary to the colours being absorbed
Explain why colour changes when ligands change
Energy gap changes and so does the frequency of light absorbed
Function of cis platin as anti cancer drug
- it binds to DNA in cancerous cells
- preventing cell division
