Electrons After reading this section you will be able to do the following: Describe the behavior of electrons in an atom. Explain how electrons allow atoms to gain or lose energy. So far, we have talked mainly about what is inside the nucleus of an atom. According to current theory, electrons are arranged in energy levels around the nucleus. The photon shown in the graphic can be considered a small bundle of energy (For more information on atoms, you may want to review the materials on magnetism.) Review: Electrons spin and rotate around the outside of the nucleus. Top 10 Mad Science-Worthy Chemistry Experiments Chemistry is a fascinating science, but it's often taught poorly in today's boring schools. Here's how chemistry should be taught: by mad scientists! Here's Neatorama's list of the Top 10 Mad Science-Worthy Chemistry Experiments: 1. Briggs-Rauscher Reaction [YouTube Clip] The Briggs-Rauscher reaction is a well known example of oscillating chemical reactions, also known as chemical clocks because the periodicity can be used to tell time. 2. Who'da thunk that Gummy Bear can be so ... violent? [YouTube Clip] 3. Mentos in various carbonated liquids. You've all seen this before. MythBusters explain: Whatever you do, don't eat a mentos then chug a mouthful of diet soda, mmkay? 4. [YouTube Clip] Yes, even elephants need to maintain good dental hygiene, but what kind of toothpaste do they use? This one's easy to do, all you need is dish soap, hydrogen peroxide, and potassium iodide: Link 5. What happens if you put a grape and nuke it in a microwave? [YouTube Clip] What just happened? Got that? 6. 7. 8.
Top 10 Mad Science-Worthy Chemistry Experiments Chemistry is a fascinating science, but it's often taught poorly in today's boring schools. Here's how chemistry should be taught: by mad scientists! Here's Neatorama's list of the Top 10 Mad Science-Worthy Chemistry Experiments: 1. Briggs-Rauscher Reaction [YouTube Clip] The Briggs-Rauscher reaction is a well known example of oscillating chemical reactions, also known as chemical clocks because the periodicity can be used to tell time. 2. Who'da thunk that Gummy Bear can be so ... violent? [YouTube Clip] 3. Mentos in various carbonated liquids. You've all seen this before. MythBusters explain: Whatever you do, don't eat a mentos then chug a mouthful of diet soda, mmkay? 4. [YouTube Clip] Yes, even elephants need to maintain good dental hygiene, but what kind of toothpaste do they use? This one's easy to do, all you need is dish soap, hydrogen peroxide, and potassium iodide: Link 5. What happens if you put a grape and nuke it in a microwave? [YouTube Clip] What just happened? Got that? 6. 7. 8.
Atoms: Neutrons Neutrons are the particles in an atom that have a neutral charge. They aren't positive like protons. They aren't negative like electrons. But don't start thinking that they aren't important. Every piece of an atom has huge importance to the way the atom acts and behaves. So, if an atom has equal numbers of electrons and protons, the charges cancel each other out and the atom has a neutral charge. You know that neutrons are found in the nucleus of an atom. Or search the sites for a specific topic. Matter: Chemical vs. Physical Changes It is important to understand the difference between chemical and physical changes. Some changes are obvious, but there are some basic ideas you should know. Physical changes are usually about states and physical states of states. Chemical changes happen on a molecular level when you have two or more molecules that interact. Chemical changes happen when atomic bonds are broken or created during chemical reactions. When you melt an ice cube (H2O), you have a physical change because you add energy. Chemical changes happen on a much smaller scale. Melting a sugar cube is a physical change because the substance is still sugar. Iron (Fe) rusts when it is exposed to oxygen gas in the air. Some chemical changes are extremely small and happen over a series of steps. The sugars glucose, galactose, and fructose all have six carbon atoms, twelve hydrogen atoms, and six oxygen atoms (C6H12O6). Or search the sites for a specific topic.
15 Awesome Chemistry Experiments You don’t need to watch Breaking Bad to know that chemistry is pretty awesome. Below we explore our favorite 15 chemistry GIFs. Melting Metal With Magnets The Science: The copper wire has a significant amount of AC electricity running through it, causing it to act like a really strong electromagnet. In the metal slug, eddy currents form due to the magnetic field the copper wire is causing while the copper wire has high frequency AC flowing through it. The metal slug’s electric resistance causes a portion of the electric energy to turn into heat, but the heat builds up until the metal slug becomes white hot and melts. Orange LED Light In Liquid Nitrogen The Science: When an LED is immersed in liquid nitrogen, the electrons lose a lot of thermal energy, even when the light isn’t turned on. Heating Mercury Thiocyanate The Science: It is an inorganic chemical compound, the salt of Hg2+ and the thiocyanate anion. Hydrogen Peroxide Catalyzed by Potassium Iodide Burning Magnesium In Dry Ice
Subatomic Particles After reading this section you will be able to do the following: List the three main subatomic particles of an atom. Discuss the positions of these particles within the atom and what electric charge they carry, if any. What are atoms made of? Now that we have talked about how atoms are combined to make other substances, let's talk about the particles that make up the atom. Protons and Neutrons Protons and neutrons make up the nucleus of an atom. If all protons are identical and all neutrons are identical, then what makes the atoms of two different elements different from each other? Review: Subatomic particles are particles that are smaller than the atom.
Future - Chemonoia: the fear blinding our minds to real dangers If you were paranoid, you might think there really was something in the water that’s damaged our sense of reason. But since about the 1960s, a strange, pervasive fear has swept across the developed world – the illusion that there is a miasma of poison threatening to invade our bodies. It’s changed the food we eat, the air we breathe, the toys we give our children. Our bete noire? Chemonoia is the excessive fear of ‘chemicals’, based on emotion more than information Scientists have a name for this phobia – ‘chemonoia’. Although you could argue that “it’s better to be safe than sorry”, some experts argue that this fear of chemicals may have some unhealthy consequences. The origins of chemonoia can be traced to the 1960s, with mounting concerns about the use of pesticides such as DDT. We are primed to fear the artificial and prefer the natural. He points to evidence showing that humans are primed to fear the artificial and prefer the natural. What can be done?
a simple view of atomic structure The nucleus The nucleus is at the centre of the atom and contains the protons and neutrons. Protons and neutrons are collectively known as nucleons. Virtually all the mass of the atom is concentrated in the nucleus, because the electrons weigh so little. Working out the numbers of protons and neutrons No of protons = ATOMIC NUMBER of the atom The atomic number is also given the more descriptive name of proton number. No of protons + no of neutrons = MASS NUMBER of the atom The mass number is also called the nucleon number. This information can be given simply in the form: How many protons and neutrons has this atom got? The atomic number counts the number of protons (9); the mass number counts protons + neutrons (19). The atomic number is tied to the position of the element in the Periodic Table and therefore the number of protons defines what sort of element you are talking about. Isotopes The number of neutrons in an atom can vary within small limits. The electrons Two important generalisations