Amongst all of the other rules in the Password Game, rule 18 seems to be the most scientific and calculate-related one. You need to go through a deep calculation which could result in satisfying rule 18. Just like the Roman Number multiplication, this one is a rather hard dam to deal with.
The Password Game rule 18 periodic table
You should have a grasp of Periodic Table Elements that indicate atomic numbers as well. Below you can find a complete list of atomic numbers that could help you in the 18th rule of the Password Game.
| Element name | Element symbol | Atomic number |
| Hydrogen | H | 1 |
| Helium | He | 2 |
| Lithium | Li | 3 |
| Beryllium | Be | 4 |
| Boron | B | 5 |
| Carbon | C | 6 |
| Nitrogen | N | 7 |
| Oxygen | O | 8 |
| Fluorine | F | 9 |
| Neon | Ne | 10 |
| Sodium | Na | 11 |
| Magnesium | Mg | 12 |
| Aluminium | Al | 13 |
| Silicon | Si | 14 |
| Phosphorus | P | 15 |
| Sulfur | S | 16 |
| Chlorine | Cl | 17 |
| Argon | Ar | 18 |
| Potassium | K | 19 |
| Calcium | Ca | 20 |
| Scandium | Sc | 21 |
| Titanium | Ti | 22 |
| Vanadium | V | 23 |
| Chromium | Cr | 24 |
| Manganese | Mn | 25 |
| Iron | Fe | 26 |
| Cobalt | Co | 27 |
| Nickel | Ni | 28 |
| Copper | Cu | 29 |
| Zinc | Zn | 30 |
| Gallium | Ga | 31 |
| Germanium | Ge | 32 |
| Arsenic | As | 33 |
| Selenium | Se | 34 |
| Bromine | Br | 35 |
| Krypton | Kr | 36 |
| Rubidium | Rb | 37 |
| Strontium | Sr | 38 |
| Yttrium | Y | 39 |
| Zirconium | Zr | 40 |
| Niobium | Nb | 41 |
| Molybdenum | Mo | 42 |
| Technetium | Tc | 43 |
| Ruthenium | Ru | 44 |
| Rhodium | Rh | 45 |
| Palladium | Pd | 46 |
| Silver | Ag | 47 |
| Cadmium | Cd | 48 |
| Indium | In | 49 |
| Tin | Sn | 50 |
| Antimony | Sb | 51 |
| Tellurium | Te | 52 |
| Iodine | I | 53 |
| Xenon | Xe | 54 |
| Caesium | Cs | 55 |
| Barium | Ba | 56 |
| Lanthanum | La | 57 |
| Cerium | Ce | 58 |
| Praseodymium | Pr | 59 |
| Neodymium | Nd | 60 |
| Promethium | Pm | 61 |
| Samarium | Sm | 62 |
| Europium | Eu | 63 |
| Gadolinium | Gd | 64 |
| Terbium | Tb | 65 |
| Dysprosium | Dy | 66 |
| Holmium | Ho | 67 |
| Erbium | Er | 68 |
| Thulium | Tm | 69 |
| Ytterbium | Yb | 70 |
| Lutetium | Lu | 71 |
| Hafnium | Hf | 72 |
| Tantalum | Ta | 73 |
| Tungsten | W | 74 |
| Rhenium | Re | 75 |
| Osmium | Os | 76 |
| Iridium | Ir | 77 |
| Platinum | Pt | 78 |
| Gold | Au | 79 |
| Mercury | Hg | 80 |
| Thallium | Tl | 81 |
| Lead | Pb | 82 |
| Bismuth | Bi | 83 |
| Polonium | Po | 84 |
| Astatine | At | 85 |
| Radon | Rn | 86 |
| Francium | Fr | 87 |
| Radium | Ra | 88 |
| Actinium | Ac | 89 |
| Thorium | Th | 90 |
| Protactinium | Pa | 91 |
| Uranium | U | 92 |
| Neptunium | Np | 93 |
| Plutonium | Pu | 94 |
| Americium | Am | 95 |
| Curium | Cm | 96 |
| Berkelium | Bk | 97 |
| Californium | Cf | 98 |
| Einsteinium | Es | 99 |
| Fermium | Fm | 100 |
| Mendelevium | Md | 101 |
| Nobelium | No | 102 |
| Lawrencium | Lr | 103 |
| Rutherfordium | Rf | 104 |
| Dubnium | Db | 105 |
| Seaborgium | Sg | 106 |
| Bohrium | Bh | 107 |
| Hassium | Hs | 108 |
| Meitnerium | Mt | 109 |
| Darmstadtium | Ds | 110 |
| Roentgenium | Rg | 111 |
| Copernicium | Cn | 112 |
| Ununtrium | Uut | 113 |
| Flerovium | Fl | 114 |
| Ununpentium | Uup | 115 |
| Livermorium | Lv | 116 |
| Ununseptium | Uus | 117 |
| Ununoctium | Uuo | 118 |
What you are asked in this section is to add an atomic number up to 200. Whatever you add to the password box may mess with other rules 9 and 7. So be careful with the element symbol you use.
To prevent any conflict with rule 9, we do not suggest using elements that are included in the Roman numbers, elements like C, D, L, M, V, and X.