Editing Group 3 element (section)

{{Short description|Group of chemical elements}}
{{for|the other group formerly named ''Group III'' (boron group)|Group 13 element}}
{{good article}}
{{Infobox periodic table group
| title       = Group&nbsp;3 {{nowrap|in the periodic table}}
| group number= 3
| trivial name=
| by element  = scandium group
| CAS         = IIIB
| old IUPAC   = IIIA
| mark        = Sc,Y,Lu,Lr
| left        = [[alkaline earth metal]]s
| right       = [[Group 4 element|group 4]]
}}
{| class="floatright"
! colspan=2 style="text-align:left;" | ↓&nbsp;<small>[[Period (periodic table)|Period]]</small>
|-
! [[Period 4 element|4]]
| {{element cell image|21|Scandium|Sc| |Solid|Transition metal|Primordial|image=Scandium sublimed dendritic and 1cm3 cube.jpg|image caption=Scandium crystals}}
|-
! [[Period 5 element|5]]
| {{element cell image|39|Yttrium|Y| |Solid|Transition metal|Primordial|image=Yttrium sublimed dendritic and 1cm3 cube.jpg|image caption=Yttrium crystals}}
|-
! [[Period 6 element|6]]
| {{element cell image|71|Lutetium|Lu| |Solid|Lanthanide|Primordial|image=Lutetium_sublimed_dendritic_and_1cm3_cube.jpg|image caption=Lutetium crystals}}
|-
! [[Period 7 element|7]]
| {{element cell image|103|Lawrencium|Lr| |Solid|Actinide|From decay}}
|-
| colspan="2" style="text-align:left" |
|-
| colspan="2" |
----
''Legend''
{| style="text-align:center; border:0; margin:1em auto;"
|-
| style="border:{{element color|Primordial}}; background:{{Element color|table mark}}; padding:0 2px;" | [[primordial element]]
|-
| style="border:{{element color|Synthetic}}; background:{{Element color|table mark}}; padding:0 2px;" | [[synthetic element]]
|-
| Atomic number color:
|}
|}

'''Group 3''' is the first group of [[transition metal]]s in the [[periodic table]]. This group is closely related to the [[rare-earth element]]s. It contains the four elements [[scandium]] (Sc), [[yttrium]] (Y), [[lutetium]] (Lu), and [[lawrencium]] (Lr). The group is also called the '''scandium group''' or '''scandium family''' after its lightest member.

The chemistry of the group 3 elements is typical for early transition metals: they all essentially have only the group [[oxidation state]] of +3 as a major one, and like the preceding main-group metals are quite electropositive and have a less rich coordination chemistry. Due to the effects of the [[lanthanide contraction]], yttrium and lutetium are very similar in properties. Yttrium and lutetium have essentially the chemistry of the heavy [[lanthanide]]s, but scandium shows several differences due to its small size. This is a similar pattern to those of the early transition metal groups, where the lightest element is distinct from the very similar next two.

All the group 3 elements are rather soft, silvery-white metals, although their hardness increases with atomic number. They quickly tarnish in air and react with water, though their reactivity is masked by the formation of an oxide layer. The first three of them occur naturally, and especially yttrium and lutetium are almost invariably associated with the [[lanthanide]]s due to their similar chemistry. 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. None of the group 3 elements have any biological role.

Historically, sometimes [[lanthanum]] (La) and [[actinium]] (Ac) were included in the group instead of lutetium and lawrencium, because the [[electron configuration]]s of many of the rare earths were initially measured wrongly. This version of group 3 is still commonly found in textbooks, but most authors focusing on the subject are against it. 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).
__TOC__