Acertain element x has four isotopes. 0.5600% of x has a mass of 83.91343 amu. 9.860% of x has a mass of 85.90927 amu. 7.000% of x has a mass of 86.90890 amu. 82.58% of x has a mass of 87.90562 amu. what is the average atomic mass of element x?

Compare and contrast physical changes with chemical changes.

A650 ml sodium bromine solution has a bromide ion concentration of 0.245 m. what is the mass (g) of sodium bromide in solution? a) 103.b)0.00155.c)16400.d) 16.4.e) 0.159

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!