Neptunium Facts - Periodic Table of the Elements

Neptunium Facts - Periodic Table of the Elements Neptunium  Basic Facts    Atomic Number: 93 Symbol: Np Atomic Weight: 237.0482 Discovery: E.M. McMillan and P.H. Abelson 1940 (United States) Electron Configuration: [Rn] 5f4 6d1 7s2 Word Origin: Named after the planet Neptune. Isotopes: 20 isotopes of Neptunium are known. The most stable of these is neptunium-237, with a half-life of 2.14 million years Properties: Neptunium has a melting point of 913.2 K, boiling point of 4175 K, heat of fusion of 5.190 kJ/mol, sp. gr. 20.25 at 20 °C; valence 3, 4, 5, or 6. Neptunium is a silvery, ductile, radioactive metal. Three allotropes are known. At room temperature it exists primarily in an orthorhombic crystalline state. Uses: Neptunium-237 is used in neutron-detection equipment. Sources McMillan and Abelson produced neptunium-239 (half-life 2.3 days) by bombarding uranium with neutrons from a cyclotron at the U. of California at Berkeley. Neptunium is also found in very small quantities associated with uranium ores. Element Classification: Radioactive Rare Earth Element (Actinide Series) Density (g/cc): 20.25 Neptunium  Physical Data Melting Point (K): 913 Boiling Point (K): 4175 Appearance: silvery metal Atomic Radius (pm): 130 Atomic Volume (cc/mol): 21.1 Ionic Radius: 95 (4e) 110 (3e) Fusion Heat (kJ/mol): (9.6) Evaporation Heat (kJ/mol): 336 Pauling Negativity Number: 1.36 Oxidation States: 6, 5, 4, 3 Lattice Structure: Orthorhombic Lattice Constant (Ã…): 4.720 References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Langes Handbook of Chemistry (1952), CRC Handbook of Chemistry Physics (18th Ed.) Return to the Periodic Table Periodic Table of the Elements Chemistry Encyclopedia

Out Now The PrepScholar Guide to ACT Science Book!

Out Now The PrepScholar Guide to ACT Science Book! SAT / ACT Prep Online Guides and Tips Do you struggle with ACT Science? You’re not alone! Science is often the ACT section students feel least comfortable with because it’s so different from the science exams you take in school. Despite this,there are very few books specifically dedicated to ACT Science. At PrepScholar, we decided to use our expert ACT knowledge to fix that.The PrepScholar Guide to ACT Science is the book for students wanting to understand and ace ACT Science. It gives an in-depth analysis of the Science section and explains why students find it so tricky. It also analyzes every single type of passage and question you’ll see on ACT Science so that nothing will be a surprise on test day. By the end of the book, you’ll know all the tricks exam makers use to try to make students select the wrong answer, and you’ll be able to see through every one of them.This book will also walk you through the fastest and most effective way to study for the Science section. Instead of try ing to cram all the science information you learned in school, we give you a short list of every science fact you could be tested on in ACT Science. They contain the only science facts you need to know, so you can put your textbooks down and focus on studying smarter, not harder. We also explain multiple ways to read and attack Science passages so you can choose the strategy that gets you your highest score. Finally, all of these insights include high-quality sample problems and explanations throughout the book so you can understand how to use these skills on real ACT Science questions. You can buy the book on Amazon in either ebook or paper form. If you find it helpful consider leaving a review or sharing it with a friend!