In the late 19th century, Russian chemist Dmitri Mendeleev published his first attempt at grouping chemical elements according to their atomic weights. There were only about 60 elements known at the time, but Mendeleev realized that when the elements were organized by weight, certain types of elements occurred in regular intervals, or periods. Today, 150 years later, chemists officially recognize 118 elements (after the addition of four newcomers in 2016) and still use Mendeleev's periodic table of elements to organize them. The table starts with the simplest atom, hydrogen, and then organizes the rest of the elements by atomic number, which is the number of protons each contains. With a handful of exceptions, the order of the elements corresponds with the increasing mass of each atom. The table has seven rows and 18 columns. Each row represents one period; the period number of an element indicates how many of its energy levels house electrons. Sodium, for instance, sits in the … [Read more...] about How Are Elements Grouped in the Periodic Table?
Group 1 elements
Polonium (Po) is a very rare and highly volatile radioactive metal. Before Polish-French physicist Marie Curie's discovery of polonium in 1898, uranium and thorium were the only known radioactive elements. Curie named polonium after her homeland, Poland. Polonium is of little use to humans, with the exception of some menacing applications: It was used as a trigger in the first atomic bomb and is also a suspected poison in a couple of high-profile deaths. In commercial applications, polonium is occasionally used to remove static electricity in machinery or dust from photographic film. It can also be used as a lightweight heat source for thermoelectric power in space satellites. Classification Polonium is located in Group 16 and period 6 in the periodic table of elements. It's classified as a metal because polonium's electrical conductivity decreases as its temperature rises, according to the Royal Society of Chemistry. The element is the heaviest metal of the chalcogens, a group of … [Read more...] about Polonium: A Rare and Highly Volatile Radioactive Element
Jeremy Berke, provided by Published 1:49 pm, Wednesday, April 11, 2018 Screenshot/ TED SpaceX, Elon Musk's rocket company, has achieved remarkable success after only a decade. Gwynne Shotwell, the company's president and COO, said at the TED 2018 Conference that part of SpaceX's success has been its ability to design rockets from a "clean sheet of paper." "We really were able to let physics drive the design of these systems," Shotwell said. SpaceX is quite literally flying high following the success (and publicity) of its launch of the Falcon Heavy rocket, which is now most powerful operational rocket on Earth. Recommended Video: Now Playing: "Apparently, there is a car in orbit around Earth," tweeted Elon Musk with a link to the live feed of the orbit with the sign 'Don't panic' on the car dashboard. It took him years to send his car with his rocket into space. 46 year old Elon Musk is member of the so-called PayPal Mafia, the founders and former … [Read more...] about SpaceX’s president revealed a key element that has made Elon Musk’s rocket company so successful
PUBLISHED: 14:39 07 April 2018 | UPDATED: 16:49 07 April 2018 Dennis Srbeny opened his goal account for Norwich City against Aston Villla. Picture: Paul Chesterton/Focus Images Ltd ©Focus Images Limited www.focus-images.co.uk +447814 482222 Our Norwich City correspondent Paddy Davitt delivers his verdict from Carrow Road 1. Lift-off? - Using Daniel Farke’s emotional spectrum there will be some Norwich City fans who now think a late play-off push is possible before taking the Premier League by storm. Flippancy aside, this was an excellent day at the office against a squad and a club who fully expect to be in the top flight next season. Norwich’s long-suffering home fans were treated to a command performance. City were tight at the back and potent up front. There was a speed and urgency to their counter-attacking motions and a freedom to their play. That really is all City fans want to see. The elusive element is that consistency which for this first season … [Read more...] about Paddy’s Pointers: Five observations from Norwich City’s thrilling 3-1 Championship win against Aston Villa
No one knows exactly when or where China's abandoned Tiangong-1 space station will return to Earth. But the map on Ted Muelhaupt's computer gives him a better idea than most. "I'm looking at it right now, and it's telling me the vehicle's not gonna land in Quito," he says. The date is Thursday, March 29, around 12:30 Pacific—63 hours before Muelhaupt predicts the 18,000-pound spacecraft, which is roughly the size of a school bus with wings, will reenter the planet's atmosphere, break apart, burn up, and rain down in bits and pieces on the earth below. "It looks like most of Texas is safe. Southern Florida, too. Although, at this resolution, I can't say for certain whether northern Florida is clear." Muelhaupt is an engineer at Aerospace Corporation, a federally funded R&D organization, where he manages the Center for Orbital and Reentry Debris Studies. Among his group's specialties are simulating uncontrolled reentries of spacecraft like Tiangong-1 and predicting when and … [Read more...] about All the Places Tiangong-1