Everything around us is made up of different elements. The air has Oxygen and Nitrogen. Plants and people have lots of Carbon. Helium is in balloons. Hydrogen is in water. Open the Symbol screen, then explore to develop your own ideas about how the atomic particles determine the name of an atom or ion. Explain your understanding: 5. What determines the element

Due to protons and electrons number.

Explanation:

The atomic particles determine the name of an atom or ion by number of protons because the number of protons determines the atomic number of an element and this atomic number distinguishes one element from another and number of electrons also be different in atoms of the same element due to chemical bonding, due to which ions are produced. So we can say that atomic particles such as proton, electron and neutrons determine the name of an atom or ion.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.