4. Protactinium-231 undergoes alpha decay as shown:
231 Pa → 4X + He
Enter the appropriate values for A and Z and the chemical symbol for
Х
A:
Z:
X:

Select the correct answer from each drop-down menu. to make a table of the elements, dmitri mendeleev sorted the elements according to their . he then split the list of elements into several columns so that elements beside each other had similar .