If 15 g of k40 remains how many half lives have passed?

The nuclear fission process releases neutrons and question 27 options: alpha particles electrons energy beta particles

Select the word from the list that best fits the definition the nuclear family into which a person is born or adopted.

I'm learning about the periodic tables and what each subject's configuration is. for example, hydrogen is 1s^1, but i don't understand how you get that. can someone me understand how to figure out how to figure this out? sorry if the question makes no sense, but it would really a lot if you could me understand! you so much if you can!