An isotope has three forms. 30% have a mass of 4 amu, 20% have a mass of 5 amu and 50% have a mass of 3 amu, Average atomic mass will be closest to

The average atomic mass will be 3.70 amu

We have to obtain the average atomic mass by multiplying the mass of each isotope in amu by the relative abundance of the given isotope as contained in the data of the question.

Hence;

Average atomic mass;

(0.30 * 4) + (0.20 * 5) + (0.50 * 3)

= 1.20 + 1.00 + 1.50

= 3.70 amu

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explanation:

answer; talc and gypsum;