Fatha tanween (ًً ) always needs alif ( ا ) to lay on
Examples;
كـتـابـاً - بيتاً - جزءاً - طعاماً
Except with letters taa marboota ( ة ) and hamza ( ء ) when it is proceeded by (ا ) .
مـرحـلـة ً - مـسـاءً