Compare the chemistry of actinoids with that of the lanthanoids with special reference to :
Chemical reactivity.

Explanation

Chemical reactivity : The earlier members of the lanthanide series are quite reactive similar to calcium but, they behave more like aluminium with increasing atomic number. The metals form oxides, sulphides, nitrides, carbides, hydrides and hydroxides. They liberate `H_(2)` from acids and water. The actinoids are more reactive than lanthanoids. They react with boiling water and are readily attacked by HCl. They combine with most non - metals at moderate temperatures. Actinoids have greater tendency to form complexes than the lanthanoids.