What is the pH of a solution with a concentration of 0.01M hydrochloric acid?

The element that has the greatest electronegativity is

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!

Helium decays to form lithium. which equation correctly describes this decay?