Which shows how much electron is in the outer layer

Write the chemical symbols for three different atoms or atomic cations with 27 electrons. asap!

During trial 2, what allowed you to determine that aluminum was the limiting reactant? check all that apply. all of the copper dissolved. all of the aluminum dissolved. the solution turned clear. the number of grams of copper(ii) chloride used in the reaction was greater than the number of grams of aluminum. the molar ratio of copper(ii) chloride to aluminum was greater than 3: 2, the equation’s molar ratio.

What is the independent variable in this investigation? mass volume sample number substance density