ILL GIVE BRAINLIEST if anyone at all knows how to do this it will save my life. if you don’t know how to do it please don’t take my points because i really need to get this done thank you ❤️ if you can only get one done that’s fine

neutrons are in the middle of the atom and the electrons, which are much smaller.

the answer is a and have a great day

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

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since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.