A chemist found one atom with 9 protons, 8 neutrons and 7 electrons. Another atom has 8 protons, 9 neutrons and 10 electrons. Which of the following statements is correct?

Both atoms are isotopes of the same element.

Both atoms are chemically non-reactive and would not interact with other atoms.

Both atoms have fulfilled the octet rule.

Both atoms have -2 electrical charge.

Both atoms have the same mass number.

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