Xbox or Ps4? Watch yall say Ps4

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

Why is retrograde motion an apparent motion

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!