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As you go down the group, there is an additional electron shell added each time (1). These electron shells hold negatively charged electrons that shield the positive nucleus from the outer shell electron. (1...

As you go down the group, there is an additional electron shell added each time (1). These electron shells hold negativley charged electrons that shield the positive nucleus from the outer shell electron. (1...

A mole is a unit for amount of substance. This unit was created because we needed a common unit which could be used to convert from eg. number of atoms/molecules to grams or concentration to grams.

The evolution of heat from a reaction is often classified as being exothermic or endothermic, but how do you know which one it is in order to assign the appropriate sign? A simple way to be sure of which typ...