[bebaycailay]

My professor said that the statement "different atoms are different because the atoms have different atomic number." is inconsistent with Dalton's atomic theory.  I don't understand why because I think this statement is right.

Thank you

[Arkcon]

Well, start with your textbook definition of Dalton's atomic theory.  (I don't have it handy.)  Then see if your statement needs changing, or if Dalton's theory is wrong, or incomplete.  However:

My professor said that the statement "different atoms are different because the atoms have different atomic number." is inconsistent with Dalton's atomic theory.

As you have stated it, there's no difference between an atom of ¹²C and ¹⁴C?

[Schrödinger]

Are we talking about Dalton's theory of atoms being indivisible here?

[ramboacid]

Consider the terminology of "atoms" and "elements."

[bebaycailay]

Well, start with your textbook definition of Dalton's atomic theory.  (I don't have it handy.)  Then see if your statement needs changing, or if Dalton's theory is wrong, or incomplete.  However:
As you have stated it, there's no difference between an atom of ¹²C and ¹⁴C?

The only difference between ¹²C and ¹⁴C is that they have different numbers of neutrons, but they have the same atomic number that makes them Carbon atoms.

[Arkcon]

And, your original statement, that they are the same atom, does that hold?