What is the structure of

How many grams of magnesium metal will react completely with 8.3 liters of 5.5m hcl? show all work

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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!