958164
TRANSITION
METALS
- All d block elements excluding
scandium (ion = [Ar] 3d^0) and
zinc (ion = [Ar] 3d^10)
- 4s orbitals are filled up first as they are lower in energy. However,
once 3d orbitals are occupied, shielding effect occurs (3d electrons
shield 4s electrons), effective nuclear charge of 4s orbitals
increases. During ion formation, 4s electrons are removed first.
- exception to general pattern of
electronic configuration: Cr ( [Ar] 3d^5
4s^1) and Cu ( [Ar] 3d^10 4s^1)
- ELECTRONIC
CONFIGURATION
- PHYSICAL PROPERTIES
(across the period)
- Atomic radii trend
- decreases slightly
Nota:
- -Across the period: * nuclear charge increases * shielding effect increases (unlike s block elements which remain constant) due to filling in of d orbitals (unlike s block metals which fills in outermost orbital) -effective nuclear charge increases slightly -atomic radii decreases slightly
- decreases slightly
- Ionic radii trend
- decreases slightly for M^3+
Nota:
- no explanation for this, no trend for M^2+
- decreases slightly for M^3+
- Boiling and melting
points
- higher than s block
elements
Nota:
- -able to use both 3d and 4s electrons for metallic bonding due to close proximity in their energies (s block elements can only use their valence electrons i.e. 1-2 electrons) -more energy needed to break the stronger metallic bond
- higher than s block
elements
- First I.E trend
- increases slightly
Nota:
- -slight increase in effective nuclear charge only -therefore slight increase in energy needed to remove a 4s electron
- increases slightly
- Density
- generally very high
Nota:
- -higher atomic mass and small atomic radius -across the period, atomic radii (vol.) decreases and atomic mass (mass) increases -density increases
- generally very high
- Electrical
conductivity
- Cu: very good
conductor of heat and
electricity
Nota:
- -due to ability to use both 3d and 4s electrons due to their close proximity in energies -unlike block s elements that are unable to use inner shell electrons due to very diff energies from the valence electrons
- Cu: very good
conductor of heat and
electricity
- Atomic radii trend
- CHEMICAL
PROPERTIES
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