La
Lanthanum · element 57
Lanthanide · Solid at room temperature
Lanthanum is a soft, ductile, silvery-white metallic chemical element with symbol La and atomic number 57. It tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It gave its name to the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table:it is also sometimes considered the first element of the 6th-period transition metals.
Key facts
Atomic mass
138.905477 u
how heavy one atom is
Phase (room temp.)
Solid
Density
6.162 g/cm³
how tightly packed it is
Melting point
1193 K (920 °C)
when solid turns to liquid
Boiling point
3737 K (3464 °C)
when liquid turns to gas
Period
6
its row in the periodic table
Group
3
its column in the periodic table
Block
F-block
the neighbourhood it lives in
Electronegativity
1.1
how strongly it pulls electrons
Electron configuration
[Xe] 5d16s2
where its electrons live
Shells
2 · 8 · 18 · 18 · 9 · 2
electrons in each layer, inside to out
Discovered by
Carl Gustaf Mosander
who found it
Appearance
silvery white
what it looks like
Source: Wikipedia