Lr Z = 103, is the last element of actinoid series. Its electronic configuration is [Rn]⁸⁶ 5f¹⁴6d¹7S² the possible oxidation state shown by it is +3.

(i) As we move from one element to another in 4f series ( Ce to Lu) the nuclear charge increases by one unit and an additional electron is added into the same inner 4f sub shell
(ii) 4f sub shell have a diffused shapes and therefore the shielding effect of 4f electrons relatively poor. Hence, with increase of nuclear charge, the valence shell is pulled slightly towards nucleus.
(iii) As a result, the effective nuclear charge experienced by the 4f electrons increases and the size of Ln³⁺ ions decreases. Lanthanoid contraction of various lanthanoids is shown in the graph.

In acid medium:
In the presence of dilute sulphuric acid, potassium permanganate acts as a very strong oxidising agent. Permanganate ions is converted into Mn²⁺ ion.
MnO₄^- + 8H⁺ + 5e^- ⟶ Mn²⁺ + 4H₂O
The oxidising nature of potassium permanganate (permanganate ion) in acid medium is illustrated in the following examples.
It oxidises ferrous salts to ferric salts.
2MnO₄ + 10Fe²⁺+ 16H⁺ ⟶ 2Mn²⁺ + 10Fe³⁺ + 8H₂O

In this method potassium manganate is treated with ozone (O₃) or chlorine to get potassium permanganate.
2MnO₄^2- + O₃ + H₂O ⟶ 2MnO₄^- + 2OH^- + O₂
2MnO₄^2- + Cl₂ ⟶ 2MnO₄^- + 2MnO₄^- + 2Cl^-

(i) It is used as a strong oxidizing agent
(ii) It is used in dyeing and printing.
(iii) It used in leather tanneries for chrome tanning.
(iv) It is used in quantitative analysis for the estimation of iron compounds and iodides.