Which atomic model was proposed as a result of j. j. thomson’s work?
a. the plum pudding model
b. the indivisible atom model
c. an atom that had a lot of empty space
d. an atom that had a concentrated nucleus

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.  

i think the answer is terrae but not 100 percent sure. ▓▬▬ §