D Block Elements

or

When blackish coloured compound is fused with in presence of air, produces a dark green colored compound potassium manganate.

Transitional metal ions having completely filled or empty d-orbitals,
ie,
or
configuration are colourless while transitional metal ions having
configuration are coloured due to transition.

purple
colourless
Hence, metal ion is colourless due to vacant d-orbitals.

is a powerful oxidising agent and gets reduced to
in neutral medium.

in alkaline medium.


in acidic medium.

Effective magnetic moment is

where, number of unpaired electrons.
A single unpaired electron has a magnetic moment of Bohr magneton .

Most of transition methods show variable valences or different oxidation states because of incomplete subshell.
The variable oxidation states are due to the participation of and electrons in bonding,
shows , and oxidation states
shows oxidation states.
Therefore, known oxidation states for both and are
and

Thorium is the radioactive element, belonging to the class of lanthanides. It is used in the treatment of cancer. It is formed by radioactive decay of uranium. Minerals (like monozite, thorite) are rich in thorium and mixed for it

has one unpaired electron in -orbital In aqueous solution this electron undergoes transition and impart colour. In , and , no unpaired electron is present in -orbital hence, they won't impart colour