How many grams of co2 are in 11 mol of the compound?

What is a number added in front of a formula in order to balance the equation

If it is an isoelectronic series select true, if not select false. o2-, s2-, se2-, te2- na+, k+, rb+, cs+ n3-, p3-, as3-, sb3- ag, cd+, sn3+, sb4+ f-, cl-, br-, i- f-, ne, na+, mg2+ s2-, s, s6+

An alpha particle is: a hydrogen atom a nucleus of helium two neutrons an electron