What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

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!

How many moles are in 123.0 grams of kclo4?

What four properties do all waves have in common