已知椭圆\(C\)方程为\( \dfrac {x^{2}}{a^{2}}+y^{2}=1\),过右焦点斜率为\(l\)的直线到原点的距离为\( \dfrac { \sqrt {2}}{2}\).
\((\)Ⅰ\()\)求椭圆\(C\)的方程;
\((\)Ⅱ\()\)设\(M(2,0)\),过点\(M\)的直线与椭圆\(C\)相交于\(E\),\(F\)两点,当线段\(EF\)的中点落在由四点\(C_{1}(-1,0)\),\(C_{2}(1,0)\),\(B_{1}(0,-1)\),\(B_{2}(0,1)\)构成的四边形内\((\)包括边界\()\)时,求直线斜率的取值范围.