Historical clue formulations

• Periodic table no. — 2023-07-22
• 12.01, for carbon: Abbr. — 2017-07-16
• Fig. on a periodic table — 2017-01-22
• No. on a periodic table — 2016-09-27
• Periodic table abbr. — 2014-07-06
• No. in chemistry — 2013-09-10
• Silver's is 107.87: Abbr. — 2013-02-24
• No. on a periodic table — 2011-02-28
• Elementary figure: Abbr. — 2010-08-29
• Bit of elementary knowledge?: Abbr. — 2009-12-12
• Al's is almost 27 — 2008-08-03
• Periodic table no. — 2008-04-02
• 1, for hydrogen: Abbr. — 2007-10-02
• Periodic table abbr. — 2007-02-14
• No. for Na or Ni — 2005-12-02
• Periodic table abbr. — 2004-04-04
• Elementary abbr. — 2003-06-07
• No. on a certain table — 2000-04-09