MOLO - Database The Molecular Logic Database is designed to provide teachers and students with easy access to our model-based activities. The activities are derived largely, but not entirely, from projects of the Concord Consortium sponsored by the National Science Foundation (NSF). The models are primarily of interactions of atoms and molecules, or rule-based genetics. The model-based activities are presented in a variety of sizes, styles, and degrees of teacher support, but a subset of Stepping Stones (See Overview of Stepping Stones) has been built to provide entries to larger domains. colored icons to indicate degree of support technological requirements links to concepts and disciplines links to standards links to some textbooks Activities can be accessed by typing an activity number in the field Jump to Activity at top right. Note: This database is in development.
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
Molecular Workbench - Database Molecular Workbench offers interactive, visual simulations and activities that have been widely used in science teaching for students of all ages. Our database is designed to provide teachers and students with easy access to our model-based activities. The activities are derived largely, but not entirely, from projects of the Concord Consortium sponsored by the National Science Foundation (NSF). The models are primarily of interactions of atoms and molecules, or rule-based genetics. All activities are accompanied by: colored icons to indicate degree of support technological requirements links to concepts and disciplines links to standards links to some textbooks Activities can be accessed by typing an activity number in the field Jump to Activity at top right. Note: This database is in development.
ChemTube3D 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.
Godlike Productions - Conspiracy Forum chemsoc timeline - flash We would like to invite you to suggest other items for inclusion in the chemsoc timeline. All genuine suggestions will be considered and those accepted will be credited to the individual responsible! The events do not have to be chemistry related - just notable discoveries or incidences that are of interest to scientists and the general public. Please Email email@example.com with your suggestion, where possible please include the date the event/discovery took place and some basic details: where it took place, who was involved and maybe some other sources of information. You can even make predictions for inventions or discoveries that you think will be made in years to come. For example if you think teleportation will be possible in 2020, why not suggest it to us! chemsoc's timeline artist Murray Robertson will create an an appropriate image to represent each successful entry. back to top
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.
Catharanthus roseus Catharanthus roseus, commonly known as the Madagascar periwinkle or rosy periwinkle, is a species of Catharanthus native and endemic to Madagascar. Other English names occasionally used include Vinca, Cape periwinkle, rose periwinkle, rosy periwinkle, and "old-maid". It was formerly classified in the Vinca genus as Vinca rosea. Synonyms Two varieties are recognized Catharanthus roseus var. roseus Synonymy for this variety Catharanthus roseus var. angustus Steenis ex Bakhuizen f. Catharanthus roseus var. albus G.Don  Catharanthus roseus var. occellatus G.Don Catharanthus roseus var. nanusMarkgr. Lochnera rosea f. alba (G.Don) Woodson Lochnera rosea var. ocellata (G.Don) Woodson Catharanthus roseus var. angustus (Steenis) Bakh. f. Catharanthus roseus var. nanus Markgr. Lochnera rosea var. angusta Steenis  Description Pale Pink with Red Centre Cultivar Cultivation and uses The species has long been cultivated for herbal medicine and as an ornamental plant.
Minerva. Storia epistemologia didattica della chimica. Cultura scientifica per il cittadino.