Editing Period 6 element (section)

==Atomic characteristics==
:{| class="wikitable sortable"
! colspan="3" | [[Chemical element]]
! [[Block (periodic table)|Block]]
! [[Electron configuration]]
|- bgcolor="{{element color|s-block}}"
|| 55  || '''Cs''' || [[Caesium]] || [[s-block]] || [Xe] 6s<sup>1</sup>
|- bgcolor="{{element color|s-block}}"
|| 56  || '''Ba''' || [[Barium]] || [[s-block]] || [Xe] 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 57 || '''La''' || [[Lanthanum]] || [[f-block]] {{ref label|Note1|a|a}} || [Xe] 5d<sup>1</sup> 6s<sup>2</sup> {{ref label|Note2|b|b}}
|- bgcolor="{{element color|f-block}}"
|| 58 || '''Ce''' || [[Cerium]] || [[f-block]] || [Xe] 4f<sup>1</sup> 5d<sup>1</sup> 6s<sup>2</sup> {{ref label|Note2|b|b}}
|- bgcolor="{{element color|f-block}}"
|| 59 || '''Pr''' || [[Praseodymium]] || [[f-block]] || [Xe] 4f<sup>3</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 60 || '''Nd''' || [[Neodymium]] || [[f-block]] || [Xe] 4f<sup>4</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 61 || '''Pm''' || [[Promethium]] || [[f-block]] || [Xe] 4f<sup>5</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 62 || '''Sm''' || [[Samarium]] || [[f-block]] || [Xe] 4f<sup>6</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 63 || '''Eu''' || [[Europium]] || [[f-block]] || [Xe] 4f<sup>7</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 64 || '''Gd''' || [[Gadolinium]] || [[f-block]] || [Xe] 4f<sup>7</sup> 5d<sup>1</sup> 6s<sup>2</sup> {{ref label|Note2|b|b}}
|- bgcolor="{{element color|f-block}}"
|| 65 || '''Tb''' || [[Terbium]] || [[f-block]] || [Xe] 4f<sup>9</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 66 || '''Dy''' || [[Dysprosium]] || [[f-block]] || [Xe] 4f<sup>10</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 67 || '''Ho''' || [[Holmium]] || [[f-block]] || [Xe] 4f<sup>11</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 68 || '''Er''' || [[Erbium]] || [[f-block]] || [Xe] 4f<sup>12</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 69 || '''Tm''' || [[Thulium]] || [[f-block]] || [Xe] 4f<sup>13</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|f-block}}"
|| 70 || '''Yb''' || [[Ytterbium]] || [[f-block]] || [Xe] 4f<sup>14</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 71  || '''Lu''' || [[Lutetium]] || [[d-block]] {{ref label|Note1|a|a}} || [Xe] 4f<sup>14</sup> 5d<sup>1</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 72  || '''Hf''' || [[Hafnium]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>2</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 73  || '''Ta''' || [[Tantalum]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>3</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 74  || '''W''' || [[Tungsten]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>4</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 75  || '''Re''' || [[Rhenium]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>5</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 76 || '''Os''' || [[Osmium]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>6</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 77 || '''Ir''' || [[Iridium]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>7</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|d-block}}"
|| 78 || '''Pt''' || [[Platinum]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>9</sup> 6s<sup>1</sup> {{ref label|Note2|b|b}}
|- bgcolor="{{element color|d-block}}"
|| 79 || '''Au''' || [[Gold]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>1</sup> {{ref label|Note2|b|b}}
|- bgcolor="{{element color|d-block}}"
|| 80 || '''Hg''' || [[Mercury (element)|Mercury]] || [[d-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup>
|- bgcolor="{{element color|p-block}}"
|| 81 || '''Tl''' || [[Thallium]] || [[p-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>1</sup>
|- bgcolor="{{element color|p-block}}"
|| 82 || '''Pb''' || [[Lead]] || [[p-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>2</sup>
|- bgcolor="{{element color|p-block}}"
|| 83 || '''Bi''' || [[Bismuth]] || [[p-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>3</sup>
|- bgcolor="{{element color|p-block}}"
|| 84 || '''Po''' || [[Polonium]] || [[p-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>4</sup>
|- bgcolor="{{element color|p-block}}"
|| 85 || '''At''' || [[Astatine]] || [[p-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>5</sup>
|- bgcolor="{{element color|p-block}}"
|| 86 || '''Rn''' || [[Radon]] || [[p-block]] || [Xe] 4f<sup>14</sup> 5d<sup>10</sup> 6s<sup>2</sup> 6p<sup>6</sup>
|}

*{{note label|Note1|a|a}} In many periodic tables, the f-block is erroneously shifted one element to the right, so that lanthanum and actinium become d-block elements, and Ce–Lu and Th–Lr form the f-block, tearing the d-block into two very uneven portions. This is a holdover from early erroneous measurements of electron configurations.<ref name="Jensen1982">{{cite journal |title=The Positions of Lanthanum (Actinium) and Lutetium (Lawrencium) in the Periodic Table |author=William B. Jensen |journal=J. Chem. Educ. |year=1982 |volume=59 |issue = 8|pages=634–636 |doi=10.1021/ed059p634|bibcode=1982JChEd..59..634J }}</ref> [[Lev Landau]] and [[Evgeny Lifshitz]] pointed out in 1948 that lutetium is not an f-block element,<ref name=Landau>{{cite book
 |author=[[Lev Landau|L. D. Landau]], [[Evgeny Lifshitz|E. M. Lifshitz]]
 |year=1958
 |title=Quantum Mechanics: Non-Relativistic Theory
 |edition=1st |volume=3
 |publisher=[[Pergamon Press]]
 |pages=256–7
}}</ref> and since then physical, chemical, and electronic evidence has overwhelmingly supported that the f-block contains the elements La–Yb and Ac–No,<ref name=Jensen1982/><ref name=Fluck/> as shown here and as supported by [[International Union of Pure and Applied Chemistry]] reports dating from 1988<ref name="Fluck">{{cite journal |last1=Fluck |first1=E. |year=1988 |title=New Notations in the Periodic Table |journal=[[Pure and Applied Chemistry|Pure Appl. Chem.]] |volume=60 |pages=431–436|doi=10.1351/pac198860030431 |url=https://www.iupac.org/publications/pac/1988/pdf/6003x0431.pdf |access-date=24 March 2012 |issue=3 |s2cid=96704008 |url-status=live |archive-url=https://web.archive.org/web/20120325152951/https://www.iupac.org/publications/pac/1988/pdf/6003x0431.pdf |archive-date=25 March 2012}}</ref> and 2021.<ref name="2021IUPAC">{{cite journal |last1=Scerri |first1=Eric |date=18 January 2021 |title=Provisional Report on Discussions on Group 3 of the Periodic Table |url=https://iupac.org/wp-content/uploads/2021/04/ChemInt_Jan2021_PP.pdf |journal=Chemistry International |volume=43 |issue=1 |pages=31–34 |doi=10.1515/ci-2021-0115 |s2cid=231694898 |access-date=9 April 2021 |archive-date=13 April 2021 |archive-url=https://web.archive.org/web/20210413150110/https://iupac.org/wp-content/uploads/2021/04/ChemInt_Jan2021_PP.pdf |url-status=live }}</ref>
*{{note label|Note2|b|b}} An exception to the [[Madelung rule]].