3. Complete the paragraph regarding isotopes by inserting keywords from the list below into the shaded boxes. physical element relative atomic mass chemically radioactive nuclei mass becoming enter text. Is one

main isotope. Accordingly, the enter text. number of that particular element. neutrons Isotopes are atoms of the same enter text. They react enter text. With different numbers of enter text. In exactly the same way, but their enter text. properties are different due to atoms of different isotopes having different enter text. Sometimes the enter text. of isotopes are unstable, which results in the element Nearly all elements exist in isotopic form, but often there is very close to the mass