Elena makes the table below to determine the number of atoms of each element in the chemical formula 3(NH4)2SO4. A table with 3 columns and 4 rows. The first column labeled element has entries nitrogen, hydrogen, sulfur, oxygen. The second column labeled calculation has entries 1 times 2 times 3 , 4 times 2 times 3, 1 times 4 times 3, 4 times 3. The third column labeled total atoms has entries 6, 24, 12, 12.
What mistake did Elena make?

She should not have multiplied the sulfur atoms by the subscript 4.
She should not have multiplied the nitrogen atoms by the subscript 2.
She should not have multiplied the oxygen atoms by the coefficient 3.
She should not have multiplied the hydrogen atoms by the coefficient 3.
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