Hi witches and wizards

What is the formula of the ionic compound composed of calcium cations and chloride anions

Of the following elements, which is the least reactive? a. c b. h c. li d. he

Achemist reacted 57.50 grams of sodium metal with an excess amount of chlorine gas. the chemical reaction that occurred is shown. na + cl2 → nacl if the percentage yield of the reaction is 86%, what is the actual yield? show your work, including the use of stoichiometric calculations and conversion factors.