The given question is incomplete. The complete question is:
Atom a and atom b have the same number of protons and neutrons but they do not have the same number of electrons. What statement describes the atoms?
The atoms have the same chemical symbol.
The atoms have the same charge.
The atoms have different atomic numbers.
The atoms have different atomic masses.
Answer: The atoms have the same chemical symbol.
Explanation:
Atomic number is equal to the number of protons for any neutral or charged specie and is specific to a particular element. Thus two elements having same atomic number will have same chemical symbols.
Mass number is the sum of number of protons and the number of neutrons.
As atoms a nd b have same protons and neutrons , they will have same atomic number and same mass number. But as the number of electrons are different , the charge on them will be different.
Thus the correct statement is the atoms have the same chemical symbol.
