How many total atoms are in the element 2c6h8o7?

First, 2C6H8O7 is NOT an element it is a Compound.

Second the formula for the compound TELLS you how many atoms are present!

2C6H8O7 = Ignoring the element symbols is 2*(6+8+7)

2*(6+8+7)= 2*(21) = 42 Atoms