Updated worked examples

Author: bjmorgan

CH40208/worked_examples/week_1_dictionaries.ipynb

@@ -403,16 +403,10 @@
     "- `.keys()` gives just keys\n",
     "- `.values()` gives just values\n",
     "\n",
-    "### 4. Why Dictionaries are Useful for Chemistry\n",
-    "- **Natural associations:** Element names → properties\n",
-    "- **Fast lookup:** Finding iron's electron count is instant, regardless of dictionary size\n",
-    "- **Extensible:** Easy to add more elements or properties\n",
-    "- **Readable:** `transition_metals['iron']` is clearer than `transition_metals[5]`\n",
-    "\n",
-    "### 5. Nested Dictionaries\n",
+    "### 4. Nested Dictionaries\n",
     "- Values can be dictionaries themselves\n",
     "- Access using multiple brackets: `dict[key1][key2]`\n",
-    "- Useful for storing multiple properties per element"
+    "- Useful, e.g., for storing multiple properties per element"
    ]
   },
   {