Atom X has an atomic number 79 and an atomic mass of 197. Atom Y has an atomic number of 76 and an atomic mass of 197. Atom Z has an atomic number of 79 and an atomic mass of 200. What two atoms are considered to be the same element and why?

atom x and atom z

Explanation:

because they have the same atomic number meaning that they have the same amount of protons. protons are what determine what type of atom it is.

po-215 i got it right on the quiz

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.