Page 38 - Curriculum Visions Dynamic Book

Neptunium (Np)
Element 93. It is a silver-coloured radioactive rare-earth metal element in the actinide series in the Periodic Table. It is a reactive element with properties similar to uranium.
In 1940 it became the first transuranium element to be artificially produced as a by-product in nuclear reactors.
Discovery
Geology
Very small amounts of neptunium are found in association with uranium ores. But most neptunium is recovered from spent fuel rods from nuclear reactors.
Biology
Neptunium is not found in living things.
Key facts...
Name: neptunium
Symbol: Np
Atomic number: 93
Atomic weight: 237
Position in Periodic Table: inner transition metal;
period 7 (actinide series)
State at room temperature: solid
Colour: silvery
Density of solid: 20.45 g/cc
Melting point: 640°C
Boiling point: 4,000°C
Origin of name: named after the planet Neptune Shell pattern of electrons: 2–8–18–32–22–9–2
Discovered by Edwin M. McMillan and P. H.Abelson in California in 1940 when they bombarded uranium with neutrons.At that time only elements as far as uranium in the Periodic Table had been discovered.That made it the first transuranium element (that is, an element after uranium) ever produced.
Technology
Used in neutron-detecting equipment.
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