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.
Since taking the helm of LG Group in 2018, Koo has focused on fostering talent and the conglomerate's future growth engines, including artificial intelligence, robotics and automobile electronics ... communication division at LG Electronics and spun off LX Holdings from the group.
Swedish truck maker Volvo Group said Thursday that profits were back up close to pre-pandemic levels in the third quarter, even if a global semiconductor shortage weighed on business ... Like the entire automotive sector, Volvo Group is facing a shortage of electronic components that is preventing it from fulfilling orders.
In this 2010 file photo, late Samsung Group Chairman Lee Kun-hee, center, is seen with his family members at the Consumer Electronics show held in Las Vegas. Courtesy of Samsung Group. By Yoon Ja-young. Oct. 25 marks the first anniversary of the death of Samsung Group Chairman Lee Kun-hee. During the past year, the bereaved family handled a huge task ... .
And that’s exactly why Nationwide Marketing Group – the leading buying and marketing group for appliance, electronics, custom integrators, furniture, bedding and outdoor living retailers – and Azione Unlimited, the preeminent group of custom integrators and manufacturers, have merged to form the most capable and results driven whole home platform.
Accenture (NYSE.ACN) will collaborate with MediaMarktSaturn Retail Group, a leading consumer electronics retailer, to transform its content production into a marketing operation focused on driving efficiency and creating ultimate relevance to the customer ... MARKETING DATA MANAGEMENT CONSUMER ELECTRONICS COMMUNICATIONS TECHNOLOGY SOFTWARE NETWORKS.
MILAN, Oct 20 (Reuters) - Italy's Tinexta is looking for potential acquisition targets in Italy and abroad, the digital services group's chief executive said on Wednesday, mentioning in particular Spain, Germany, France and Great Britain... The group also has cyber ...
Apple’s largest supplier, Taiwan’s Foxconn TechnologyGroup, has been making busy moves getting in the trendy game of electric vehicles. On Monday, the electronics manufacturer unveiled three EV prototypes at its “Technology Day” event in Taipei.
Futures are flat as investors await another big batch of earnings reports. Here’s what we’re watching ahead of Wednesday’s action ... Omnicom Group slipped 1.4% premarket ... Interactive Brokers Group slipped 1.4% premarket. The electronic broker reported a decline in earnings per share for the recent quarter compared with a year ago ... Chart of the Day.