If you mixed chlorine, lithium and nickel together which two elements would be the most reactive?

He reactivity of an element increases towards the top and right of the periodic table (until the column of noble gases is reached). Chlorine's outer shell contains 7 electrons that make it very reactive. Helium is a noble gas and is non reactive. Elements found in the middle of the table, like nickel and iron, are reactive, but less reactive than chlorine