What kind of simple machine is a shovel

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

Air can be considered a mixture. which statement does not explain why?

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!