Answer:
E
Explanation:
100 minutes is 5 half lives ( 100 min/20 min/half life)
= (1/2 )^5
1 x 10^20 * (1/2)^5 = 3.125 x10^18 molecules
When an atomic nucleus emits an alpha particle it decay into an atom with atomic number 2 less and mass number 4 less. Thus Thorium 230 decay as follows.
230 90Th -------> 226 88Th + 4 2 He
thorium is in the atomic number 90 thus it during alpha decay it reduces to atomic number 88 while its 230 mass number reduces to 226
Answer:
increases as you move down a group as the number of electrons increases. Therefore, the atomic radius increases as the group and energy levels increase
Explanation:
answer:an arrangement of elements in columns, based on a set of properties that repeat from row to row
Explanation:
hope this helps love <3