Cerium
Table:
Cerium
Pronunciation	/ˈsɪəriəm/ ​(SEER-ee-əm)
Appearance	silvery white
Standard atomic weight Ar, std(Ce)	140.116(1)
Atomic number (Z)	58
Group	group n/a
Period	period 6
Block	f-block
Element category	Lanthanide
Electron configuration	[Xe] 4f1 5d1 6s2

Electrons per shell

2, 8, 18, 19, 9, 2
Phase at STP	solid
Melting point	1068 K ​(795 °C, ​1463 °F)
Boiling point	3716 K ​(3443 °C, ​6229 °F)
Density (near r.t.)	6.770 g/cm3
when liquid (at m.p.)	6.55 g/cm3
Heat of fusion	5.46 kJ/mol
Heat of vaporization	398 kJ/mol
Molar heat capacity	26.94 J/(mol·K)
Oxidation states	+1, +2, +3, +4 (a mildly basic oxide)
Electronegativity	Pauling scale: 1.12
Ionization energies

1st: 534.4 kJ/mol
2nd: 1050 kJ/mol
3rd: 1949 kJ/mol
(more)

Atomic radius	empirical: 181.8 pm
Covalent radius	204±9 pm
Natural occurrence	primordial
Speed of sound thin rod	2100 m/s (at 20 °C)
Thermal expansion	γ, poly: 6.3 µm/(m·K) (at r.t.)
Thermal conductivity	11.3 W/(m·K)
Electrical resistivity	β, poly: 828 nΩ·m (at r.t.)
Magnetic ordering	paramagnetic
Magnetic susceptibility	(β) +2450.0·10−6 cm3/mol (293 K)
Young's modulus	γ form: 33.6 GPa
Shear modulus	γ form: 13.5 GPa
Bulk modulus	γ form: 21.5 GPa
Poisson ratio	γ form: 0.24
Mohs hardness	2.5
Vickers hardness	210–470 MPa
Brinell hardness	186–412 MPa
CAS Number	7440-45-1
Naming	after dwarf planet Ceres, itself named after Roman deity of agriculture Ceres
Discovery	Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803)
First isolation	Carl Gustaf Mosander (1838)

Based on the table, determine whether the statement is entailed, neutral, or refuted. Conclude with JSON {"answer": "YOUR ANSWER"} — nothing else.

Assertion: Cerium was first discovered in the 1830s.

answer: entailed