What are the inner transition elements? Decide which of the following atomic numbers at the atomic numbers of the inner transition elements: 29, 59, 74, 95, 102, 104?
A green chromium compound (A) on fusion with alkali gives a yellow compound (B) which on acidification gives an orange coloured compound (C). ‘C’ on treatment with NH4Cl gives an orange coloured product (D), which on heating decomposes to give back (A). Identify A, B, C and D. Write equations for reactions.
Reaction with sulphur: Heating lanthanoids with sulphur form corresponding sulphides.
2Ln + 3S → Ln2S3