⚠️Will give brainlist⚠️

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!

Which of the following is not an assumption that scientists must make about the natural world? a. regularity b. causality c. predictability d. plausibility

An unknown insoluble substance displaced the water shown. it's mass is indicated on the triple beam balance. mass = a. 694 b. 693.5 c. 693.0 d.693.8