Chemical Elements.com - Neptunium (Np)

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Basic Information

Name: Neptunium
Symbol: Np
Atomic Number: 93
Atomic Mass: (237.0) amu
Melting Point: 640.0 °C (913.15 K, 1184.0 °F)
Boiling Point: 3902.0 °C (4175.15 K, 7055.6 °F)
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

Number of Energy Levels: 7

First Energy Level:

Second Energy Level:

Third Energy Level:

Fourth Energy Level:

Fifth Energy Level:

Sixth Energy Level:

Seventh Energy Level:

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

MLA Format for Citing This Page

Bentor, Yinon. Chemical Element.com - Neptunium. <http://www.chemicalelements.com/elements/np.html>.

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