CHALLENGE 83

These are the 17 US States whose abbreviations are also chemical element symbols. They appear in the order of the periodic table of elements (except the last one): Nebraska - NE - Neon (10); Alabama - AL - Aluminium (13); Arkansas - AR - Argon (18); California - CA - Calcium (20); South Carolina - SC - Scandium (21); Minnesota - MN - Manganese (25); Colorado - CO - Cobalt (27); Georgia - GA - Gallium (31); Missouri - MO - Molybdenum (42); Indiana - IN - Indium (49); Louisiana - LA - Lanthanum (57); North Dakota - ND - Neodymium (60); Pennsylvania - PA - Protactinium (91); Montana - MT - Meitnerium (109); New Hampshire - NH - Nihonium (113); Florida - FL - Flerovium (114); Maryland - MD - Mendelevium (101)