5all phosphorus atoms have the same(1) atomic number
(2) mass number
(3) number of neutrons plus the number of electrons
(4) number of neutrons plus the number of protons

the answer is the first option

explanation:

just googled it m8. not that hard

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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.

            and  

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.