When 0.200 l of 0.2 m hcl is mixed with 0.200 l of 0.200 m naoh in a coffee-cup calorimeter, the temperature of the mixture increases from 22.15°c to 23.48°c. if the densities of the two solutions are 1.00g/ml, what is the value of ∆hrxn for the following reaction? ( use the specific heat of water of 4.18 j/g⁰c)

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!