![[ATOM]](atom.gif) |
Neptunium
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Information valid for Np-237 unless otherwise noted
Basic Information
Symbol: Np
Atomic Number: 93
Mass: (237.0)
Melting Point: 640.0 C
Boiling Point: 3902.0 C
Number of Protons/Electrons: 93
Number of Neutrons: 144
Classification: Rare Earth
Crystal Structure: Orthorhombic
Density @ 293 K: 20.45 g/cm3
Color: Unknown
Atomic Structure
![[Bohr Model of Neptunium]](b0093.gif) |
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Number of Energy Levels: 7
First Energy Level: 2
Second Energy Level: 8
Third Energy Level: 18
Fourth Energy Level: 32
Fifth Energy Level: 23
Sixth Energy Level: 8
Seventh Energy Level: 2
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Isotopes
| Isotope |
Half Life |
| Np-235 |
1.08 years |
| Np-236 |
155000.0 years |
| Np-236m |
22.5 hours |
| Np-237 |
2140000.0 years |
| Np-238 |
2.11 days |
| Np-239 |
2.35 days |
| Np-240 |
1.03 hours |
| Np-240m |
7.22 minutes |
Facts
Date of Discovery: 1940
Discoverer: E.M. McMillan
Name Origin: After the planet Neptune
Uses: No uses known
Obtained From: Man-made