The Periodic Table Made Simple: A Beginner's Guide to the Elements

The periodic table is a fundamental tool in chemistry, organizing all known elements in a structured and concise manner. It may seem intimidating at first glance, but fear not! In this beginner's guide, we'll break down the periodic table into bite-sized pieces, making it easy to understand and navigate. So, grab your lab coat and safety goggles as we embark on a journey through the elemental wonders!

What is the Periodic Table?

The periodic table is like a cheat sheet for chemists—it contains essential information about every known element. Elements are substances that cannot be broken down into simpler substances by chemical means. They are the building blocks of matter and the universe. The periodic table organizes elements based on their atomic number, which represents the number of protons in the nucleus of an atom.

Structure of the Periodic Table:

The periodic table is organized into rows and columns, also known as periods and groups, respectively. Each row represents a new energy level in which electrons are arranged around the nucleus, while each column features elements with similar chemical properties. At the top of the table, you'll find nonmetals, on the left, you'll find alkali metals, and on the right, you'll find noble gases.

Understanding Element Symbols:

Each element is represented by its chemical symbol, usually consisting of one or two letters. For example, oxygen is represented by "O," hydrogen by "H," and gold by "Au" (from its Latin name "aurum"). Some symbols may not match the element's name in English, so be prepared for a few surprises!

Atomic Number and Atomic Mass:

Every element has an atomic number and an atomic mass. The atomic number tells you the number of protons in an atom's nucleus, and for neutral atoms, it's also the number of electrons. The atomic mass represents the total mass of the protons and neutrons in the nucleus. This information is essential for understanding an element's behavior and properties.

Groups and Periods:

Groups are the columns of the periodic table, and elements within the same group share similar properties. For example, Group 1 contains alkali metals like lithium and sodium, which are highly reactive with water. Periods, on the other hand, are the rows, and elements within the same period have the same number of electron shells.

The Magic of Valence Electrons:

Valence electrons are the electrons in the outermost energy level of an atom. These electrons are crucial in determining how atoms react and bond with other elements. Elements in the same group have the same number of valence electrons, contributing to their similar chemical behavior.

Metals, Nonmetals, and Metalloids:

The periodic table classifies elements into three categories: metals, nonmetals, and metalloids. Metals are typically shiny, good conductors of heat and electricity, and malleable. Nonmetals, on the other hand, are usually dull, poor conductors, and can be solids, liquids, or gases. Metalloids exhibit characteristics of both metals and nonmetals, making them unique.

Conclusion:

Congratulations! You've just scratched the surface of the amazing world of the periodic table. This essential tool for chemists allows us to unlock the secrets of the elements and their interactions. As you delve deeper into the fascinating realm of chemistry, the periodic table will be your faithful guide, revealing the wonders and complexities of the material universe. So, keep exploring, keep experimenting, and keep learning about the building blocks that make our world so incredibly diverse and intriguing!

Finding IEDs With ‘Metal Detectors On Steroids’

The joint Afghan National Army – U.S. forces counter improvised explosive device team of seven soldiers walked down the dusty rural road in Shamulzai District, Afghanistan, ahead of their convoy; scanning the route with their eyes for subtle clues that might help them visually identify an improvised explosive device, or IED, hidden on the road.

When they see nothing, they verify as much by sweeping the same area with their VMR-2 Minehound and VMC-1 Gizmo metal detectors in a slow precise manner before walking ahead.

“We walked a good four and a half (kilometers) in front of the whole convoy because we had just recently been hit with an IED on the route back (to Forward Operating Base Sweeney),” said Staff Sgt. Antonio Barajas, 3rd Platoon, 5th Battalion, 20th Infantry Regiment, Task Force 1st Squadron, 14th Cavalry Regiment, out of Joint Base Lewis-McChord, Wash. “All seven of us had Gizmos and Minehounds (and were) out there clearing the whole road so the rest of the convoy could make it back to FOB Sweeney safely.”

“The Gizmo is just an easy (to use) metal detector used to identify metal or you can switch it to minerals,” explained Barajas when asked to describe the two devices used that day.

“It’s a lot like the metal detectors you see men on the beach with, but on steroids,” said Pfc. Niko Williams, also from 3rd Platoon, 5-20 Infantry, Task Force 1-14 Cavalry.

The use of such gadgetry has been a blessing to both ANA and International Security Assistance Forces in Afghanistan.

For Barajas and his team, the MineHound’s ground penetrating radar enabled them to discover a secondary IED earlier in the day, prior to the IED strike on their convoy. That IED was only a hundred meters forward of the one that hit them.

Without the MineHound, there stood a chance Barajas’ team may have missed that roadside bomb.

The Minehound and Gizmo metal detectors are “the current state-of-the-art technology dual sensor detectors capable of detecting command wires, non-metallic and low-metallic signature IEDs using ground penetrating radar,” according their product description online. “In addition to GPR, the Minehound uses Vallon’s advanced metal detector sensor, which is the same sensor used in Vallon’s VMC-1 Gizmo detector to find both metallic and non-metallic threats.”

The Vallon Company claims to have more than 2,000 Minehound detectors currently in use in Afghanistan. They, along with the Gizmo, have become an invaluable item in finding IEDs and weapons caches before they can be used against ANA or ISAF forces.

The use of the Minehound and Gizmo detectors started with combat engineers and explosive ordnance disposal personnel, but they are now issued to non-EOD units such as Battle Company, 5-20 Infantry, to aid in the discovery of IEDs and weapons caches.

Since the onset of the Afghan War in 2001, homemade bombs have increasingly become the insurgent’s weapon of choice in Afghanistan and certainly their most effective weapon.  Almost 60 percent of all coalition forces wounded or killed in Afghanistan since the start of the war in 2001 have been due to IEDs, according to a May 2011 report from the Joint Improvised Explosive Device Defeat Organization, a U.S. Department of Defense organization located in Washington D.C.

To complicate matters, insurgents in Afghanistan have been increasingly constructing IEDs to circumvent simple metal detectors. Some IEDs contain rudimentary materials such as wooden boards, foam rubber, and plastic containers. The finished product contains very little metal making it difficult for a traditional metal detector to pick up, but not for the Minehound with its ground penetrating radar.

Increasingly compact, collapsible, light-weight metal detectors, such as the MineHound and Gizmo, are finding IEDs with more frequency than ever before, all of which has reduced the number of injuries or deaths to Afghan civilians, ANA and ISAF troops. In the hands of an infantry platoon, or similar-type unit, they are also being used to find weapons caches which often provide the insurgency with ample arms to fight for weeks or months.

“In the orchards (the Minehound and Gizmo are) good because that’s where they often hide the caches,” said Barajas. “So far we’ve found two caches with the Gizmo and Minehounds, and also with the ANA helping us out with their resources.”

Without doubt, improved technological devices such as the VMR-2 Minehound and VMC-1 Gizmo metal detectors are helping coalition troops across Afghanistan.

“It helps a lot when we’re in the orchards or going through the towns when we use the Gizmos and Minehounds because it also allows if something does get missed by sight it will pick it up,” said Williams. “That’s what makes the Gizmo and Mine Hound so important,” said Williams. “It helps make sure people are not being taken out of the fight … (that) you’re keeping them in,” said Williams.

By Sgt. Christopher McCullough

 From www.army.mil 

Not-So-Precious: Stripping Gold From AFM Probes Allows Better Measurement of Picoscale Forces

Gold is not necessarily precious—at least not as a coating on atomic force microscope (AFM) probes.

JILA researchers found that removing an AFM probe's gold coating—until now considered helpful—greatly improved force measurements performed in a liquid, the medium favored for biophysical studies such as stretching DNA or unfolding proteins. As described in Nano Letters,* stripping the gold from the diving-board-shaped probe, or cantilever, with a brief chemical bath improved the precision and stability of force measurements about 10-fold. The advance is expected to quickly and broadly benefit the fields of biophysics and nanoscience.

JILA is a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.

"What I find interesting about this experiment is it's so incredibly simple. It takes a minute to strip the gold off a commercial cantilever and you get a 10-fold improvement in force precision," says NIST/JILA physicist Thomas Perkins.

To measure forces at the molecular scale, an AFM's cantilever attaches to a molecule with its pointed end and pulls; the resulting deflection of the cantilever is measured. The forces are in the realm of piconewtons (pN), or trillionths of a newton. A unit of force, one newton is roughly the weight of a small apple.

Cantilevers are typically made of silicon or silicon nitride and coated with gold on both sides to reflect light. Perkins discovered the gold coating was a problem while his research group was probing the folding and unfolding of protein molecules over time periods of seconds to minutes. The group previously improved AFM position stability** and holds a related patent,*** but then discovered that the force was drifting. "It's counterintuitive," says Perkins. "Everyone has assumed you needed gold for the enhanced reflectivity, when in fact, gold is clearly the dominant source of force drift on short and long time scales."

"Gold exhibits a sort of complex elastic property in high-precision measurements," Perkins explains. "When you bend gold, it creeps a little bit, like silly putty. Further, the lore in the field is that gold can crack, it can age, and molecules can bind to it—all of which may change its mechanical properties. This problem is even worse when you do biological experiments in liquid."

AFM force measurements in liquid typically have had precision (error range) of plus or minus 5 to 10 pN. By stripping the gold JILA researchers reduced the error by 10 times, to about 0.5 pN for measurements on both short and long timescales. Researchers can now precisely measure fast processes, such as proteins folding and unfolding 50 times per second, over long time periods of several minutes. Significantly, the results were achieved with commercially available microscopes and cantilevers, so the practical benefits can be applied quickly for any AFM force measurements and imaging. AFM can now compete with optical traps and magnetic tweezers in terms of sensitivity.

The research was supported by the National Science Foundation and NIST.

* A.B. Churnside, R.M.A. Sullan, D.M. Nguyen, S.O. Case, M.S. Bull, G.M. King and T.T. Perkins. Routine and timely sub-piconewton force stability and precision for biological applications of atomic force microscopy. Nano Letters. Published online June 13.

** See the Mar. 24, 2009, NIST Tech Beat article, "Making a Point: Picoscale Stability in a Room-Temperature AFM" at www.nist.gov/public_affairs/tech-beat/tb20090324.cfm#afm.

*** U.S. Patent 7,928,409, April 19, 2011, Real-time, active picometer-scale alignment, stabilization and registration in one or more dimensions, T.T. Perkins, G.M. King and A.R. Carter.

Small Planets Don't Need Stars With Heavy Metal Content To Form

J.D. Harrington

Headquarters, Washington                                   

202-358-5241

j.d.harrington@nasa.gov

 

Michele Johnson

Ames Research Center, Moffett Field, Calif.

650-604-6982

michele.johnson@nasa.gov

 

WASHINGTON -- The formation of small worlds like Earth previously was thought to occur mostly around stars rich in heavy elements such as iron and silicon. However, new ground-based observations, combined with data collected by NASA's Kepler space telescope, shows small planets form around stars with a wide range of heavy element content and suggests they may be widespread in our galaxy.

A research team led by Lars A. Buchhave, an astrophysicist at the Niels Bohr Institute and the Centre for Star and Planet Formation at the University of Copenhagen, studied the elemental composition of more than 150 stars harboring 226 planet candidates smaller than Neptune.

"I wanted to investigate whether small planets needed a special environment in order to form, like the giant gas planets, which we know preferentially develop in environments with a high content of heavy elements," said Buchhave. "This study shows that small planets do not discriminate and form around stars with a wide range of heavy metal content, including stars with only 25 percent of the sun's metallicity." 

Astronomers refer to all chemical elements heavier than hydrogen and helium as metals. They define metallicity is the metal content of heavier elements in a star. Stars with a higher fraction of heavy elements than the sun are considered metal-rich. Stars with a lower fraction of heavy elements are considered metal-poor.

Planets are created disks of gas and dust around new stars. Planets like Earth are composed almost entirely of elements such as iron, oxygen, silicon and magnesium.

The metallicity of a star mirrors the metal content of the planet-forming disk. Astronomers have hypothesized that large quantities of heavy elements in the disk would lead to more efficient planet formation. It has long been noted that giant planets with short orbital periods tend to be associated with metal-rich stars.

Unlike gas giants, the occurrence of smaller planets is not strongly dependent on the heavy element content of their host stars. Planets up to four times the size of Earth can form around stars with a wide range of heavy element content, including stars with a lower metallicity than the sun. The findings are described in a new study published in the journal Nature.

"Kepler has identified thousands of planet candidates, making it possible to study big-picture questions like the one posed by Lars. Does nature require special environments to form Earth-size planets?" said Natalie Batalha, Kepler mission scientist at NASA's Ames Research Center at Moffett Field, Calif. "The data suggest that small planets may form around stars with a wide range of metallicities -- that nature is opportunistic and prolific, finding pathways we might otherwise have thought difficult."

The ground-based spectroscopic observations for this study were made at the Nordic Optical Telescope on La Palma in the Canary Islands; Fred Lawrence Whipple Observatory on Mt. Hopkins in Ariz.; McDonald Observatory at the University of Texas at Austin; and W.M. Keck Observatory atop Mauna Kea in Hawaii.

Launched in March 2009, Kepler searches for planets by continuously monitoring more than 150,000 stars, looking for telltale dips in their brightness caused by passing, or transiting, planets. At least three transits are required to verify a signal as a planet. Follow-up observations from ground-based telescopes are also needed to confirm a candidate as a planet.

Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed the Kepler mission development.

Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

The Space Telescope Science Institute in Baltimore archives hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington.

For more information about the Kepler mission, visit http://www.nasa.gov/kepler.

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The Air Force Mad Scientist

Staff Sergeant Jonathan Burg is suiting up for his upcoming operation, but this airmen is no doctor.  Today’s patient is a chunk of metal.  That’s because Burg’s job isn’t quite ordinary.  Everything he works on is located behind closed doors – or in this case, black canvas – in the non-destructive inspection shop .

What does that mean, exactly?  Find out:

Video by Airman First Class Roman Weber