(1) Cerium is quite electropositive and reacts slowly with cold water and quite quickly with hot water to form cerium hydroxide
(2) Cerium exhibits three oxidation states, +2, +3 and +4 but the +2 state is rare
(3) Cerium cannot be isolated and purified compared to other Lanthanides
(4) There are four isotopes of cerium that occur naturally
(5) Cerium metal reacts with all the halogens except I$_2$
$\begin {array} {1 1}(2) \;and \;(5) \\ (3)\;and (5) \\ (1)\;and\;(4) \\ (2)\;and \;(3) \end {array}$
