;

Periodic Table Element Comparison: Compare Elements - Helium vs Promethium

Compare Helium and Promethium

Compare Helium and Promethium on the basis of their properties, attributes and periodic table facts. Compare elements on more than 90 properties. All the elements of similar categories show a lot of similarities and differences in their chemical, atomic, physical properties and uses. These similarities and dissimilarities should be known while we study periodic table elements. You can study the detailed comparison between Helium vs Promethium with most reliable information about their properties, attributes, facts, uses etc. You can compare He vs Pm on more than 90 properties like electronegativity , oxidation state, atomic shells, orbital structure, Electronaffinity, physical states, electrical conductivity and many more.

Facts

Helium
2
He
4.002602
Gas
Colorless
noble gas
18
helium family or neon family 
1
p
1s2
N/A
-268.93 °C
2
CAS7440-59-7
Neighborhood Elements of Helium
Promethium
61
Pm
145
Solid
Silver
lanthanide
N/A
 
6
f
[Xe] 4f5 6s2
1.1×103 °C
3×103 °C
2, 8, 18, 23, 8, 2
CAS7440-12-2
Neighborhood Elements of Promethium

History

History
The element Helium was discovered by Pierre Janssen in year 1895 in Sweden and United Kingdom. Helium derived its name from from the Greek word helios, meaning 'sun'
The element Promethium was discovered by Chien Shiung Wu in year 1945 in United States. Promethium derived its name derived its name from from Prometheus of Greek mythology who stole fire from the Gods and gave it to humans

Presence: Abundance in Nature and Around Us

Ppb by weight (1ppb =10^-7 %)
0.23
0.23
N/A
5.5×10-7%
7.2×10-10%
N/A
N/A
None
None
None
None
None

Crystal Structure and Atomic Structure

31 pm
22.423540616247 cm3
32 pm
140 pm
0.007
helium Spectrum
424.2, 424.2, 424.2 pm
π/2, π/2, π/2
Fm_ 3m
225

Face Centered Cubic

helium Crystal Structure
205 pm
19.961453744493 cm3
N/A
N/A
8×103
promethium Spectrum
N/A
N/A
N/A
N/A

Simple Hexagonal

promethium Crystal Structure

Atomic and Orbital Properties

Atomic Number
Number of Electrons (with no charge)
Number of Protons
Mass Number
Number of Neutrons
Shell structure (Electrons per energy level)
Electron Configuration
Valence Electrons
Oxidation State
Atomic Term Symbol (Quantum Numbers)
Shell structure
2
2
2
4.002602
2.002602
2
1s2
1s2
 
1S0
helium Shells
61
61
61
145
84
2, 8, 18, 23, 8, 2
[Xe] 4f5 6s2
4f5 6s2
 2;3
6H5/2
promethium Shells

Isotopes - Nuclear Properties

Isotopes
Naturally occurring stable isotopes:
3He, 4He.
Naturally occurring stable isotopes:
None.

Chemical Properties: Ionization Energies and electron affinity

0
N/A
0 kJ/mol
2372.3, 5250.5 kJ/mol
3
N/A
50 kJ/mol
540, 1050, 2150, 3970 kJ/mol

Physical Properties

0.1785 g/l
22.423540616247

 

N/A
N/A
N/A
N/A


 

N/A
N/A
N/A

 

N/A
N/A
N/A

 

0.1513 W/(m K)
N/A

 

Diamagnetic
N/A
-5.9×10-9
-2.36×10-11
-1.05×10-9

 

1.000035

 

970 m/s
7.264 g/cm3
19.961453744493

 

46 GPa
18 GPa
33 GPa
0.28


 

N/A
N/A
N/A

 

1.3×106 S/m
7.5×10-7 m Ω
N/A

 

15 W/(m K)
0.000011 K-1

 

N/A
N/A
N/A
N/A
N/A

 

N/A

 

N/A

Thermal Properties - Enthalpies and thermodynamics

N/A
-268.93 °C
5.19 K
N/A

 

0.02 kJ/mol
0.083 kJ/mol
N/A
1.1×103 °C
3×103 °C
N/A
N/A

 

7.7 kJ/mol
290 kJ/mol
N/A

Regulatory and Health - Health and Safety Parameters and Guidelines

CAS7440-59-7
RTECSMH6520000
2.2
1963
N/A
0
N/A
1
0

 

N/A
N/A
CAS7440-12-2
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A

 

N/A
N/A