What happens at the molecular level when a compound dissolves in water? This interactive animation explores how negative and positive ions in sodium chloride (table salt) collide with water molecules and become separated from each other to become a solution. The model does an effective job of depicting how the water molecules disrupt the attraction between the positive sodium ions and the negative chloride ions, and then become stabilized by attractions to the atoms in the water molecule.
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Editor's Note: This animation could be very helpful in building a foundation to understand covalent and ionic bonding. It is paced so that students ranging from grades 6-12 can comprehend what is happening, especially if they refer to the glossary for unfamiliar words. Be sure not to miss the additional materials in this large collection. Author Mark Bishop also created two textbooks in introductory chemistry (available in free digital format), Power Point presentations for teachers, tutorials, student guides, and more.
Metadata instance created
May 2, 2011
by Caroline Hall
April 18, 2012
by Lyle Barbato
AAAS Benchmark Alignments (2008 Version)
4. The Physical Setting
4D. The Structure of Matter
6-8: 4D/M1a. All matter is made up of atoms, which are far too small to see directly through a microscope.
6-8: 4D/M1b. The atoms of any element are like other atoms of the same element, but are different from the atoms of other elements.
6-8: 4D/M1cd. Atoms may link together in well-defined molecules, or may be packed together in crystal patterns. Different arrangements of atoms into groups compose all substances and determine the characteristic properties of substances.
6-8: 4D/M3cd. In solids, the atoms or molecules are closely locked in position and can only vibrate. In liquids, they have higher energy, are more loosely connected, and can slide past one another; some molecules may get enough energy to escape into a gas. In gases, the atoms or molecules have still more energy and are free of one another except during occasional collisions.
6-8: 4D/M8. Most substances can exist as a solid, liquid, or gas depending on temperature.
9-12: 4D/H2. The number of protons in the nucleus determines what an atom's electron configuration can be and so defines the element. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons.
9-12: 4D/H7a. Atoms often join with one another in various combinations in distinct molecules or in repeating three-dimensional crystal patterns.
9-12: 4D/H8. The configuration of atoms in a molecule determines the molecule's properties. Shapes are particularly important in how large molecules interact with others.
9-12: 4D/H10. The physical properties of compounds reflect the nature of the interactions among its molecules. These interactions are determined by the structure of the molecule, including the constituent atoms and the distances and angles between them.
11. Common Themes
6-8: 11B/M1. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly. They are also used for processes that are too vast, too complex, or too dangerous to study.
6-8: 11D/M3. Natural phenomena often involve sizes, durations, and speeds that are extremely small or extremely large. These phenomena may be difficult to appreciate because they involve magnitudes far outside human experience.
%0 Electronic Source %A Bishop, Mark %D 2011 %T An Introduction to Chemistry: Dissolving Sodium Chloride %V 2013 %N 23 May 2013 %9 application/flash %U http://preparatorychemistry.com/NaCl_flash.htm
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