Worked Problem #2a: Must show work and submit in PDF file. Put your answer for the % and the mass in the box below and remember to BOX your answer on the submitted work.

Given the information below, calculate the abundance and mass for the missing isotope of cesium. Report your isotope mass to FOUR digits after the decimal point. For your answer, ______%, _______amu. Both must be entered below.

Isotope Symbol	Isotope Abundance	Isotope Mass
136Ce	0.19%	135.9071 amu
138Ce	0.25%	137.9060 amu
140Ce	???? %	???? amu
142Ce	11.08%	141.9092 amu