The atomic numbers and masses must added up on both sides of the equation just as we must have the same number of atoms on each side of an equation when it is balanced. Ejection of a "thing" with 2 protons and 2 nuetrons is a He nucleus which is an alpha particle.
88Ra226 ==>86X222 + 2He4
All we have done is write the Ra isotope down and remove 2 protons (88-2=86) and 4 in mass number (2 protons + 2 neutrons = mass of 4 and 226-4=222). This forms a new element X, so what is it. We look on the periodic table and find an element with atomic number 86, then replace the X with the symbol for the element. If you don't have periodic table handy, here is one on the web.
http://www.webelements.com/
Writing subscripts and superscripts is not easy on the computer; if I have made an error I will correct it with a follow up post.
Which element results if two protons and two neutrons are ejected from a radium nucleus with atomic number 88 and mass number 226? (I must show my workings), but i am totally lost!!!
2 answers