Looking at the periodic table, which pair of elements will have the same number of valence electrons? a. silicon and germanium b. nitrogen and oxygen c. silicon and phosphorus d. hydrogen and helium

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5

650.j is the same amount of energy as? 2720cal1550cal650.cal2.72cal

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!