Group 3 element
Yttrium and lutetium have essentially the chemistry of the heavy lanthanides, but scandium shows several differences due to its small size.
Lawrencium is strongly radioactive: it does not occur naturally and must be produced by artificial synthesis, but its observed and theoretically predicted properties are consistent with it being a heavier homologue of lutetium.
Historically, sometimes lanthanum (La) and actinium (Ac) were included in the group instead of lutetium and lawrencium, because the electron configurations of many of the rare earths were initially measured wrongly.
Some authors attempt to compromise between the two formats by leaving the spaces below yttrium blank, but this contradicts quantum mechanics as it results in an f-block that is 15 elements wide rather than 14 (the maximum occupancy of an f-subshell).
Physical, chemical, and electronic evidence overwhelmingly shows that the correct elements in group 3 are scandium, yttrium, lutetium, and lawrencium:[1][2][3][4][5][6][7] this is the classification adopted by most chemists and physicists who have considered the matter.
[8] Many textbooks however show group 3 as containing scandium, yttrium, lanthanum, and actinium, a format based on historically wrongly measured electron configurations:[4] Lev Landau and Evgeny Lifshitz already considered it to be "incorrect" in 1948,[5] but the issue was brought to a wide debate only in 1982 by William B.
[8] While the 2021 IUPAC report noted that 15-element-wide f-blocks are supported by some practitioners of a specialised branch of relativistic quantum mechanics focusing on the properties of superheavy elements, the project's opinion was that such interest-dependent concerns should not have any bearing on how the periodic table is presented to "the general chemical and scientific community".
[15][16] As noted by the 2021 IUPAC report, Sc-Y-Lu-Lr is the only form that simultaneously allows for the preservation of the sequence of atomic number, avoids splitting the d-block into "two highly uneven portions", and gives the blocks the correct widths quantum mechanics demands (2, 6, 10, and 14).
[17] But the same is true of thorium which is never disputed as an f-block element,[8][4] and this argument overlooks the problem on the other end: that the f-shells complete filling at ytterbium and nobelium (matching the Sc-Y-Lu-Lr form), not at lutetium and lawrencium (as in Sc-Y-La-Ac).
In gaseous atoms, the d-shells complete their filling at copper (3d104s1), palladium (4d105s0), and gold (5d106s1), but it is universally accepted by chemists that these configurations are exceptional and that the d-block really ends in accordance with the Madelung rule at zinc (3d104s2), cadmium (4d105s2), and mercury (5d106s2).
[27][28] In fact, Gadolin's yttria proved to be a mixture of many metal oxides, that started the history of the discovery of the rare earths.
[25] In 1869, Russian chemist Dmitri Mendeleev published his periodic table, which had an empty space for an element above yttrium.
Among these was ytterbia (a component of the old erbia),[22] which Swedish chemist Lars Fredrik Nilson successfully split in 1879 to reveal yet another new element.
In 1907, French scientist Georges Urbain,[34] Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James[35] all independently discovered a new element within ytterbia.
Ironically, Charles James, who had modestly stayed out of the argument as to priority, worked on a much larger scale than the others, and undoubtedly possessed the largest supply of lutetium at the time.
The first atoms of lawrencium were produced by bombarding a three-milligram target consisting of three isotopes of the element californium with boron-10 and boron-11 nuclei from the Heavy Ion Linear Accelerator (HILAC).
[47] In 1992, the IUPAC Trans-fermium Working Group named the nuclear physics teams at Dubna and Berkeley as the co-discoverers of element 103.
[43] Like other groups, the members of this family show patterns in their electron configurations, especially the outermost shells, resulting in trends in chemical behavior.
[51][52] Most of the chemistry has been observed only for the first three members of the group; chemical properties of lawrencium are not well-characterized, but what is known and predicted matches its position as a heavier homolog of lutetium.
The chemistries of group 3 elements are thus mostly distinguished by their atomic radii:[53] yttrium and lutetium are very similar,[56] but scandium stands out as the least basic and the best complexing agent, approaching aluminium in some properties.
[64] Scandium, yttrium, and lutetium tend to occur together with the other lanthanides (except short-lived promethium) in the Earth's crust, and are often harder to extract from their ores.
[70] Yttrium has the same trend in occurrence places; it is found in lunar rock samples collected during the American Apollo Project in a relatively high content as well.
[72] The principal commercially viable ore of lutetium is the rare-earth phosphate mineral monazite, (Ce,La,etc.
The main mining areas are China, United States, Brazil, India, Sri Lanka and Australia.
[80] Scandium is known to have reached the food chain, but in trace amounts only; a typical human takes in less than 0.1 micrograms per day.
The element is known to damage cell membranes of water animals, causing several negative influences on reproduction and on the functions of the nervous system.
