2.3.2 in the malpighian body name four of the substances which are represented by arrows​

Afamily is one another name for a group on the table of elements.

What does the symbol (–hfus) indicate in a phase change?

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!