In chemistry, a group (also known as a family) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table, but the f-block columns (between groups 2 and 3) are not numbered. The elements in a group have similar physical or chemical characteristics of the outermost electron shells of their atoms (i.e., the same core charge), as most chemical properties are dominated by the orbital location of the outermost electron.
There are three systems of group numbering. The modern numbering group 1 to group 18 is recommended by the International Union of Pure and Applied Chemistry (IUPAC). It replaces two older naming schemes that were mutually confusing. Also, groups may be identified by their topmost element or have a specific name. For example, group 16 is variously described as oxygen group and chalcogen.
CAS and old IUPAC numbering
Two earlier group number systems exist: CAS (Chemical Abstracts Service) and old IUPAC. Both use numerals (Arabic or Roman) and letters A and B. Both systems agree on the numbers. The numbers indicate approximately the highest oxidation number of the elements in that group, and so indicate similar chemistry with other elements with the same numeral. The number proceeds in a linearly increasing fashion for the most part, once on the left of the table, and once on the right (see List of oxidation states of the elements), with some irregularities in the transition metals. However, the two systems use the letters differently. For example, potassium (K) has one valence electron. Therefore, it is located in group 1. Calcium (Ca) is in group 2, for it contains two valence electrons.
In shooting, a shot grouping, or simply grouping, is the placement of multiple shots on a target, the shots taken in one shooting session. The closeness of the grouping, the nearness of all the shots to each other, is a measure of the accuracy of a weapon, and a measure of the shooter's consistency and skill.
Uses of the term
For firearms that shoot one round at a time, a shot grouping can be used to measure the accuracy of the system comprised out of weapon as well as the precision and uniformity of the ammunition by fixing the weapon into position on a test mount, and aiming it at a target. Multiple shots using rounds from same type and batch are fired to observe how the weapon groups the shots. If a person holds the weapon and shoots it, the grouping measures the combination of the person's skill and the weapon's accuracy.
In shotgun shooting, the grouping is also called the pattern. The pattern is the spread of shot from a single shotgun shell, measured as the smallest circle containing all the shots on the target. The barrel of a shotgun is designed to deliver a wide or narrow grouping, depending on the expected use. Shooting at close range indicates a cylinder bore barrel to deliver a wide grouping, while for hunting at longer distances such as 50 yards or meters, a choke is recommended for a tighter grouping.
ENVIRONMENTAL group GreenpeacePhilippines urged the Department of Energy (DoE) to immediately address the looming power outages in the country caused by "outdated" energy system, which can be done through giving more focus on transitioning to smart, flexible renewable energy.
It took a major international investment group with $279bn under its control to break through the climate-laden rhetoric of geopolitics last week ... Jotzo says it was notable, coming from the usually conservative global energy advisory group, but it was just a scenario “and not a projection”.
Nevada is poised to be a leader in the renewable energy revolution, but we don’t have a plan for how to achieve the state’s goals while protecting our irreplaceable biodiversity ... Each of these renewable energy technologies comes with environmental impacts ... Jean Su is the group’s energy justice director.
Authorities said the family of nine tubers went over an 8-foot dam near DukeEnergy's SteamStation sometime Wednesday night ... Four family members were rescued Thursday afternoon after a Duke Energy employee saw them stranded near the dam by the utility’s steam station.
It procured 83% of its total energy from renewable sources ... On top of these initiatives, Burberry is also a principal partner of The Living Wage Foundation and a member of the GlobalLiving Wage Initiative steering group ... These are some of the initiatives that have helped the group achieve one of the highest ESG ratings of all UK shares.
Isiah Crawford, seven, and Teresa Villano, 30, were tubing with seven members of their extended family on Wednesday afternoon when they went over a deep drop into the DukeEnergy dam ... The group got into trouble when several of their round inflatable rafts came untied and some floated over the Duke Energy dam in Eden, North Carolina.
“According to the country’s applicable laws, the destruction of power pylons and public facilities by individuals and groups is considered a crime,” said Faiz MohammadZadran, an expert in the energy sector.
EDEN, N.C ... The victim’s identity is yet to be confirmed ... A group of nine people were floating down the river on inflatable tubes when they went over a dam ... The group went over a dam that’s about 8 feet (2.5 meters) high next to a DukeEnergy plant ... ....
The drilling would occur on over 600 square miles of federal land scattered across the energy-rich states ...Court says federal agency did not improperly withhold records from environmental group ... The agency's allies in the case included the WesternEnergyAlliance industry group and the state of Wyoming, where Republican Gov ... Energy & Environment.
The future of clean energy is hot. Temperatures hit 800 Celsius in parts of solar energy plants and advanced nuclear reactors ...Department of Energy’s (DOE) Argonne National Laboratory, Messner is among a group of engineers who are discovering better ways to predict how materials will behave under high temperatures and pressures.
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NEW YORK (AP) — Once they could finally get off the court, the Milwaukee Bucks feasted their eyes on a welcome sight in the locker room ... "You put so much emotion and so much energy and time in it. For this group to be rewarded with a huge win in a Game 7 in overtime, it’s just a great group. You feel great for the group, great for the players.” ... ___ ... .
The point from the tie gives Hungary a chance to advance to the knockout stage of the tournament, albeit they would have to defeat Germany in its last Group F game Wednesday in Munich... “The scenario was great; it really gave them that extra burst of energy that they needed.”.