I believe it’s a or c. and those links are so annoying i had to start a new account
If the element has not become an ion yet, then there is 73 electrons.
Number of protons = number of electrons**
**only when the element has not form an anion or cation.
I think the answer is non reactive. As the outer shells gets filled ,valency decreases, so reactivity also decreases.
All the best
Do it is big buns vs big buns equals 23