class Isotope extends Element implements Serializable, IIsotope, Cloneable {

    @Override
    public Integer getMassNumber() {
        return this.massNumber;
    }

    public  Isotope(String elementSymbol);
    public  Isotope(int atomicNumber, String elementSymbol, int massNumber, double exactMass, double abundance);
    public  Isotope(int atomicNumber, String elementSymbol, double exactMass, double abundance);
    public  Isotope(String elementSymbol, int massNumber);
    public  Isotope(IElement element);

}