Chlorine is used by textile manufacturers to bleach cloth. excess chlorine is destroyed by its reaction with sodium thiosulfate, na 2 s 2 o 3 : na 2 s 2 o 3(aq) + 4cl 2g) + 5h 2 o (ako)  2 nahso4(aq) + 8hcl (aq) a. how many moles of na 2 s 2 o 3 are needed to react with 0.12mol of cl 2

0.030 mol Na2S2O3

From the balanced equation, the molar ratio of Na2S2O3:Cl2 is 1:4.

∴ Moles of Na2S2O3 = 0.12 mol Cl2 x (1 mol Na2S2O3/4 mol Cl2)

= 0.030 mol Na2S2O3

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.