13.0 Periodicity Flashcards
Why do the first row of d block elements have similar physical and chemical properties?
Relatively small range in atomic radii
Why are the d block elements similar in atomic radii
Electron shielding from the 3d level causes a small increases for the effect of increasing nuclear charge on the 4s electrons
Physical properties of Transitional metals
-High electrical and thermal conductivity
-High melting point
-malleable
-High tensile strength
-Ductile
-Iron, Cobalt and nickel are ferromagnetic
Why are all the 4s and 3d electrons involved in bonding and form the delocalized sea of electrons
The 4s and 3d levels are close in energy
Chemical Properties of Transitional metals
-Form compounds with more than one oxidization number
-Form a variety of complex ions
-Form colour compounds
-Acts as catalysts
Why is Zn not a Transitional metal?
Zinc does not show properties of transitional metals as it has full 3d level in standard and ionized states.
Why do Transitional metals show multiple oxidization states?
Due to successive ionization energy
Why is the successive ionization energy for Transitional metals gradual compared to something like Ca+3
the 4s and 3d levels in the transitional metals are closer together, for the calcium the third electron must be removed from the inner 3p level and dictates a huge jump in energy requirement.
What oxidization number is common for Sc to Cr?
+3
What oxidization is common past Cr and why?
+2, increased nuclear charge of the later elements makes it hard to ionize to +3
What element has the highest oxidization state in transitional metals?
manganese, it decreases by -1 after manganese.
What properties do oxidization of transitional metals after +3 show?
covalent
What does compounds with high oxidization state tend to be?
Oxidizing agents. E.g. potassium dichromate VI
What is a coordinate bond?
Covalent bond formed by a lone pair of electrons from one atom
What are lignads?
a species that uses a lone pair of electrons to form coordinate bond with the central metal ion
What is a complex?
Central ion that is surrounded by molecules or ions which possesses a lone pair of electrons
What are ligands in terms of Acid and bases?
Lewis bases
How are coordination numbers determined?
The number of coordinate bonds from the ligands to the central ion
Different ligands show what?
different colours
What shape does a coordination number of 2 show?
Linear
What shape does a coordination number of 4 show?
Square planer, tetrahedral
What shape does a coordination number of 6 show?
octahedral
Why do transition metals show magnetic properties?
they contain unpaired electrons
Diamagnetism?
Very weak magnetic field, has paired electrons
