Explanation:
elements are based on electrical conductivity
Elements have neutral charges such as Na so if X has 72 protons + charges then it must also have 72 electrons with - charges
hope that helps
N -3
Ba +2
Sr +2
F -1
I -1
Ca +2
Mg +2
S -2
S -2
Al +3
//
Ba3N2
SrF2
CaI2
MgS
Al2S3
//
I don't really understand 2.
substance is matter of particular or definite chemical constitution ex: iron, methane
mixture are two or more substances that have been combined to retain their individual chemical characteristics ex: salt water, cola
