Types of Bonds Custom Search Bonding Links <-- Back to electronegativity Electronegativity Differences between atoms can be used to determine the type of bonding that occurs. If the difference between 2 atoms is small (less than 1.7) the bond is covalent. If the difference is large (greater than 1.7) the bond is considered ionic. Exceptions- HF is covalent not ionic (difference of 1.9) BF3 is covalent (difference of 2.0) BeF2 is covalent (difference of 2.5) Covalently bonded atoms will share their electrons in order to form a stable outer electron shell that has 8 electrons. This is called an octet of electrons. Ionic is 1 minute in. Ionic bonded atoms will transfer one or more electrons from the less electronegative element (a metal) to the more electronegative element (a nonmetal) as to achieve an octect of electrons. This results in the formation of 2 ions. The bond is a strong electrostatic attraction formed by 2 opposing ions. Chemical Demonstration Videos
Recursos TIC para aprender la tabla periódica Investigadores rusos han logrado sintetizar el elemento 118 de la tabla periódica. El docente puede aprovechar este avance científico para trabajar en el aula los elementos químicos y su posición en la tabla periódica. Para ello puede utilizar alguna de las cinco aplicaciones en línea recomendadas: juegos interactivos, vídeos sobre los elementos químicos, tablas periódicas dinámicas, apuntes y actividades online y una calculadora científica para la clase de Química. FUENTE: RIA Novosti Para comenzar la actividad, se puede sondear los conocimientos previos de química que poseen los alumnos mediante una pequeña reflexión en voz alta sobre el título de la noticia. Tras ello se pedirá a los estudiantes que lean detenidamente el texto, anotando todos aquellos términos que no entiende para comentar su significado, en gran grupo, ayudados por el profesor y apuntes básicos de química. Son muchas las aplicaciones que pueden ser utilizadas como material de apoyo para la clase de química. Química
Chemical Bonds Selected by the SciLinks program, a service of National Science Teachers Association. Copyright 2001. For an explanation of the significance of this logo go to: Because of the tendency of atoms to complete their outer energy shells with the stable number of electrons for each shell, atoms with incomplete shells have a tendency to gain electrons, lose electrons or share electrons. Atoms that have gained or lost electrons become ions. Oppositely charged ions form ionic bonds. Ionic bonds The following animation shows how ions of sodium and chlorine are formed. The oppositely charged ions in the animation will be attracted to each other and form an ionic bond. Covalent bonds Atoms can fill their outer shells by sharing electrons. In the animation, two hydrogen atoms share each other's electrons and form a molecule of hydrogen. Covalent bonds can be nonpolar, or polar. Hydrogen bonds Back to Chemistry Back to Steinberg Web Pages © Dr.
Molecular Workbench - An Interface to the Molecular World It's All About Carbon If you have questions about climate change, please e-mail them to All Things Considered or call the show at 202-898-2395. When the subject is global warming, our mood is usually "uh-oh." Which makes sense, because a warmer Earth will lead to all kinds of disruptions and expensive adjustments that we could do without. NPR and National Geographic take a year-long journey around the globe to explore how climate is shaping people and people are exploring climate. Odd Todd But there is another way to think about all of this. What we have done here is a chemistry lesson, one that begins with the elemental cause of global warming: the behavior of the carbon atom. And since carbon atoms are rather small, we have turned our atom into a cartoon. This is the introductory segment of a five-part series that explains how carbon atoms form bonds, break apart and create the conditions that can lead to global warming. In this, the first lesson, we introduce our atom. So take a look.
Middle School Chemistry | Download Free Science Activities, Access Chemistry Multimedia, Find Information on Workshops DNA-RNA-Protein DNA carries the genetic information of a cell and consists of thousands of genes. Each gene serves as a recipe on how to build a protein molecule. Proteins perform important tasks for the cell functions or serve as building blocks. The flow of information from the genes determines the protein composition and thereby the functions of the cell. The DNA is situated in the nucleus, organized into chromosomes. The document has two levels, basic and advanced. Learn how to navigate in the document
AP Chemistry Review Activities AP Chemistry Interactive Review Activities In keeping with the new framework for AP Chemistry beginning in 2013 - 2014, I am indicating here if the topic to which a review activity relates has been dropped from the curriculum. It will be identified as excluded (Excluded) to indicate that the College Board has specifically excluded it. I will leave the reviews here, however, in case some of you find them useful. These are not graded assignments. Each time you reload the activity, the problems will be in a different order, and the answers will be reshuffled!
Membranes Organize Cellular Complexity Membranes organize proteins and other molecules enabling the cell to run much more efficiently than if everything were floating freely. Mitochondrial membranes, for example, keep protein assembly lines together for efficient energy production. And the lysosome safely holds enzymes that would destroy essential proteins if released into the cytoplasm. Membrane-enclosed vesicles form packages for cargo so that they may quickly and efficiently reach their destinations. Real life complexity inside an insulin-producing pancreas cell. Image courtesy of Dr. Phospholipids provide the framework for all membranes in the cell. When phospholipids are placed into water, they organize themselves into a structure called a bilayer. The shape and chemical nature of phospholipids drives them to organize themselves one level further. Phospholipid membranes form a barrier that most molecules cannot cross. Membrane proteins represent a large number of proteins with diverse functions.
Chemistry Freeware On this page I post reviews and links to freeware chemistry programs available for download at other sites around the internet. All of the programs are ones that I have used, or currently use. None-the-less, I take no responsiblity for any problems you might experience as a result of installing any of these applications. Unless otherwise noted, the programs are for Windows systems. ACD/ChemSketch 12 Freeware. MolView.Org is a web-based molecular viewing and modeling tool. Discovery Studio Visualizer 4. ChemAxon produces a wide range of Java-based chemistry tools, and they offer free academic licenses (you must register with them). The Virtual Laboratory from the ChemCollective is a personal favorite. KnowItAll Academic Edition - In a continued commitment to academia, Bio-Rad is offering this completely FREE and fully functional software package to promote learning and research in the academic community. Orbital Viewer is a program for drawing orbitals.