All actinides

• Have short-lived isotopes
• Exhibit variable valency
• Are synthetic elements
• Include elements beyond atomic number 104.

The magnetic moment of a manganese ion (Z = 25) is 6.92 BM. The symbol of the ion is

• Mn²⁺
• Mn⁴⁺
• Mn⁺ 
• Mn⁷⁺

•  (n – 1 )d and (n – 2) f orbitals
• (n – 1)d and ns orbitals
• (n – 1)d orbitals
• (n – 1) f orbitals

Why is radius of Fe²⁺ less than that of Mn²⁺?

Write outer electronic configuration of lanthanoids.

Write the general electronic configuration of the transition elements of d-block elements.

What happens when chromates are kept in acidic solution and dichromate in alkaline solution?

What type of magnetic behaviour is shown by the molecules containing unpaired electrons?

280.

Write the formula of the compound in which the Mn metal is in +7 oxidation state.