If you have 8 g of a radioactive element there will be Of the radioactive element left after one half life

4g of the radioactive element present

Explanation:

Radioactive elements are atoms that are unstable in normal conditions and are converted in another different atoms.

1 half life express the time that is need to decay the half of the initial amount of the radioactive element.

If initially we have 8g of the radioactive element, after 1 life we will have 8g/2 =

4g of the radioactive element present

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.  

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