PLS HELP ME THIS IS DUE TODAY BRO ILL BRAINLIST U JUST DO THE ONES U KNOW WAJDHWNDIGB!

Helium «-» 2 «-» 2

Carbon «-» 6 «-» 2,4

Neon «-» 10 «-» 2,8

Hydrogen «-» 1 «-» 1

Magnesium «-» 12 «-» 2,8,2

Chlorine «-» 17 «-» 2,8,7

Aluminium «-» 13 «-» 2,8,3

Helium: atomic number 2. EC 2

Neon: atomic number 10. EC 2,8

hydrogen: atomic number 1. EC 1

magnesium: atomic number 12. EC 2,8,2

chlorine: atomic number 17. EC 2,8,7

Aluminum: atomic number 13. EC 2,8,3

Explanation: hope this helped

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%