How many electrons are used to draw the electron-dot structure for calcium chloride (an ionic compound with the formula cacl2)?

Lewis structure is drawn in following steps,

1) Calculate the total number of electrons in valence shell of all elements,

                                             Ca    =    2

                                             Cl     =    7

                                             Cl     =    7
                                           ------------------------
              Total valence electrons   =    16

2) Draw central atom (Ca) in center surrounded by remaining elements (Cl) and draw a single bond between central atom and surrounding atoms. Subtract 2 electrons per bond from total valence electrons. And divide the remaining electrons on the most electronegative element. The structure will be as shown below,

Result:
           So it required 16 electrons to draw the Lewis Structure of CaCl₂