code: String getMetalAtomicSymbol(String metalName) {
          if ("aluminium".equals(metalName)) {
              return "Al";
          } else if ("magnesium".equals(metalName)) {
              return "Mg";
          } else if ("gallium".equals(metalName)) {
              return "Ga";
          } else if ("indium".equals(metalName)) {
              return "In";
          } else if ("thallium".equals(metalName)) {
              return "Tl";
          } else if ("germanium".equals(metalName)) {
              return "Ge";
          } else if ("tin".equals(metalName)) {
              return "Sn";
          } else if ("lead".equals(metalName)) {
              return "Pb";
          } else if ("arsenic".equals(metalName)) {
              return "As";
          } else if ("antimony".equals(metalName)) {
              return "Sb";
          } else if ("bismuth".equals(metalName)) {
              return "Bi";
          }
  
          return null;
      }
docs: Translates a metal's name into it's atomic symbol.
  
  @param metalName The name of the metal, e.g. lead
  @return The given metal's atomic symbol e.g. Pb or null if none exist.