D and f block

d-block elements

Elements lying in the middle of the periodic table belonging to groups 3 to 12.

electronic configuration

The general electronic configuration for d-block elements is (n - d1-10ns1-2.

Transition element

An element with incompletely filled d orbitals in its ground state or any oxidation state.

Lanthanoids

The 14 elements following lanthanum, from Cerium (58) to Lutetium (71), belonging to the first inner transition series.

Actinoids

The 14 elements following actinium (89), from Thorium (90) to Lawrencium (103), belonging to the second inner transition series.

4d-transition series

Elements with atomic numbers 39 (Y) to 48 (Cd) containing incomplete 4d orbitals.

Lanthanoid Contraction

The decrease in atomic and ionic radii of the transition metals as atomic number increases due to filling of 4f orbitals.

Ionization enthalpy

The energy required to remove an electron from an atom, showing slight and irregular variation in transition metals.

Oxidation state

Variable oxidation states shown by transition metals due to participation of (n-1)d and ns electrons in bond formation.

Paramagnetic

Metals that possess unpaired electrons and usually exhibit magnetic properties.

Coloured compounds

Transition metals form coloured ions due to incompletely filled d-orbitals and unpaired electrons.

Interstitial compounds

Compounds formed when smaller atoms fit into the voids of the metallic lattice, such as carbon in steel.

Mischmetall

An alloy consisting of a lanthanoid metal (~95%) and iron (~5%) used in Mg-based alloys for making bullets and lighter flint.

Preparation of Potassium dichromate

Prepared by fusion of chromate ore (FeCr2O4) with sodium carbonate in excess of air.

Potassium permanganate

Prepared from potassium hydroxide and manganese dioxide in the presence of an oxidizing agent.

Complex formation

Transition metals can form complexes due to vacant d-orbitals, smaller size, and higher charge on cations.

Catalytic properties

Transition metals are used as catalysts due to incomplete d-orbitals, large surface area, variable oxidation states, and ability to form complexes.

Chromate and dichromate ions

Inter-convertible in aqueous solution depending on pH, with Cr having the same oxidation state in both.

Magnetic properties of lanthanoids

Lanthanoids exhibit less complex magnetic properties compared to actinoids.

Actinoids properties

Show higher oxidation states and are radioactive, with more complex magnetic properties compared to lanthanoids.