Which of the following statements is incorrect ?

Among actinoids, Np and Pu exhibit +7 oxidation state 

$C{e}^{+4}$  act as oxidizing agent and $E{u}^{+2}$ act as reducing agent

$C{e}^{+3}(Z=58)$  to  $Y{b}^{+3}(Z=70)$, size gradually increases

Mischmetal consist of lanthanoid metal  $(\approx 95\%)$ and iron  $(\approx 5\%)$ and traces of S,C,Ca and Al