If an atom has 13 electrons how many electron shells does it have

What is the percent by mass of oxygen in fe2o3

For each of the following compounds, decide whether the compound's solubility in aqueous solution changes with ph. if the solubility does change, pick the ph at which you'd expect the highest solubility. you'll find ksp data in the aleks data tab. compounds does solubility change with ph

What substance has a mass of 9.5g and volume of 2.1cm^3