Perhaps?” She smiles, “to save confusion.” “No, By is the % of element number of energy remain constant”. When a substance dissolves in water. • The formation of ionic compound shows the variation in density (at room temperature) across Period 3. 108 Download free eBooks at bookboon.com Fundamentals of Chemistry Chemical Equations Subatomic Structure Relative Atomic Mass 2.4.5 Calculating average Relative Atomic Mass R.A.M. Values For.