Which statement is true? Isotopes of a given element have equal numbers of neutrons. Isotopes are atoms of different elements which have the same mass. Isotopes of a given element have equal numbers of protons and neutrons. Isotopes of a given element have very similar chemical properties. Isotopes are atoms that have gained or lost electrons.

some sources quote the lethal dose, for an average 170lbs opiate-naive individual is between 75 and 375 mg

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.