The element nitrogen has an atomic weight of 14.0 and consists of two stable isotopes nitrogen-14 and nitrogen-15. the isotope nitrogen-14 has a mass of 14.0 amu and a percent natural abundance of 99.6 %. the isotope nitrogen-15 has a percent natural abundance of 0.370 %. what is the mass of nitrogen-15?

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.