# Mole concept- to find isotopic formula

1. Jul 10, 2012

### xiphoid

1mole of diatomic element X2 contains 34 and 40 moles of electrons and neutrons respectively, the isoptopic formula of the element is?
1. The problem statement, all variables and given/known data
1mole of diatomic element X2 contains 34 and 40 moles of electrons and neutrons respectively

2. Relevant equations
all the basic ones!

3. The attempt at a solution
The answer from my point of view should be 17X37

2. Jul 10, 2012

### Staff: Mentor

Re: Mole concept- to find isopopic formula

Looks good.

3. Jul 11, 2012

### dharavsolanki

Re: Mole concept- to find isopopic formula

I am assuming that the isotopic formula of the element asks you for that notation where you display both the atomic mass (protons + neutrons) and atomic number (protons).

Something like 1H1

Then, let's start from the beginning.

34 moles of electrons in X2 = 17 electrons in one atom.
Similarly, 20 neutrons in one atom.

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With this in mind, what will be the atomic mass? What will be the atomic number?