Neon has three naturally occurring isotopes: Ne-20 with mass 19.9924 amu and a natural abundance of 90.60 %, Ne-21 with mass 20.9938 amu and a natural abundance of 0.260 %, and Ne-22 with mass 21.9914 amu and a natural abundance of 9.20 %

20.191 a.m.u

Explanation:

To calculate the average atomic mass for neon, we take into consideration the individual isotopes and their masses. We multiply the percentage of each of their abundances by their masses and add the results together to arrive at the value.

This can be done as follows;

[90.60/100 * 19.9924] + [0.26/100 * 20.9938] + [9.2/100 * 21.9914] = 18.113 + 0.055 + 2.023 = 20.191 a.m.u

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

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