Download Building Atoms - Community Science Workshop Network

Building Atoms Category: Chemistry Type: Make & Take Rough Parts List: 3 1 1 1 1 Blocks of different colored clay Box of toothpicks Box of skewers Plastic cup Sheet of paper Periodic Table Tools List: Drill Drill bit Plastic tray Permanent marker How To: Label which color plasticine represents the electrons, protons and neutrons. Roll pea-­‐sized balls to represent electrons. © 2013 Mission Science Workshop. All Rights Reserved worldwide. When linking to or using MSW content, images, or videos, credit MUST be included. To build protons and neutrons, roll balls that are twice the size of the electrons. Looking at the periodic table, identify the element of Hydrogen (H). What are the atomic number and atomic mass of Hydrogen? For Hydrogen, the atomic number is 1 and the atomic mass is 1. Build 1 electron and 1 proton. Break a toothpick in half. Push the electron onto one end of the toothpick. Push a proton onto the other end. This is a simple model of a Hydrogen atom. © 2013 Mission Science Workshop. All Rights Reserved worldwide. When linking to or using MSW content, images, or videos, credit MUST be included. Find Carbon (C) on the periodic table and identify its atomic number and mass. Determine the number of electrons, protons and neutrons needed to build a carbon model. To support the model, turn a cup upside down and drill a hole through the bottom. Break off approximately 1/3 of the skewer. Stick the skewer through the hole in the cup and into a large piece of clay to keep it upright. Arrange all of the protons (6 total) and neutrons (6 total) into a ball to build the atom’s nucleus. Place the nucleus on top of the skewer. © 2013 Mission Science Workshop. All Rights Reserved worldwide. When linking to or using MSW content, images, or videos, credit MUST be included. Using a mix of long and short toothpicks arrange the electrons (6 total) around the nucleus. Make a label for your atom. Include the name, number of electrons, protons and neutrons. Fine Points: → The protons and neutrons might have to be pressed together hard so that they stick to each other. Try and keep the overall shape spherical. → If you want to make the model more accurate, make the electrons tiny specs of clay and the protons and neutrons much larger. Then use bamboo skewers instead of toothpicks, since the average distance between a nucleus and its electrons is actually much, much greater than shown in this model. Concepts Involved: •
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Atoms are made up of electrons, protons and neutrons. Electrons are negatively charged, protons are positively charged and neutrons have no charge. In the periodic table, elements are organized based on their atomic masses. This also gives information on some of their properties. Using the atomic mass and atomic numbers, the numbers of electrons, protons and neutrons in an atom can be determined. Focus Questions: 1. Why do you think different elements have different weights? 2. Pick an element from the fifth row of the Periodic Table. Calculate the number of protons, neutrons, and electrons in an atom of that element. Repeat with an element from the seventh row. 3. What is the difference is between electrons, protons and neutrons?
Elaboration: Atoms can be described as building blocks; we are made up of billions and billions of atoms. Atoms themselves are made up of electrons, protons and neutrons. The center part of an atom is a dense nucleus that’s made up of the positively charged protons and electrically neutral neutrons. A cloud of the negatively charged electrons surrounds the nucleus. The electrons in this activity are around half the size of the protons and neutrons. In reality, electrons are much smaller and around 2000 times lighter than protons and neutrons. They are moving constantly and a cloud is a good way to visualize them. That’s one limitation in these models – they’re static and don’t represent the constant movement of an atom’s particles. Electrons are attracted to the positively charged protons. This means that for every electron in a neutral atom, there is one proton. © 2013 Mission Science Workshop. All Rights Reserved worldwide. When linking to or using MSW content, images, or videos, credit MUST be included. An element is a pure substance in its simplest form consisting of only one type of atom. There are over 120 known elements, both natural and man-­‐made. Only the first 98 elements are known to occur naturally on Earth and these include, hydrogen, helium, gold, silver and copper. Humans are made of billions of atoms but only 40 elements! The periodic table is an important tool in chemistry. The periodic table lists 118 elements and recognizes several more unnamed ones. They are organized based on atomic number, which also gives information on how the electrons are arranged and how they will react with other. The standard form of the table is comprised of a large grid of elements, positioned above a double row of elements. Each square of the periodic table houses an element, and contains information about it. Here is an example: Hydrogen (H) and Carbon (C) as they appear on the periodic table. There are three main parts in each element’s squares. One or two letters represent the name of each element, and the first letter is always capitalized. For some elements one or two letters from the element's common name are used, such as C for carbon, while others are based on their Latin names such as Au for gold. The number above the name is the atomic number which tells us how many and protons are in an atom of the element. Atoms are neutrally charged, so for every positively charged proton in an atom there is a negatively charged electron. For example, the atomic number for carbon is 6, meaning that it has 6 protons and 6 electrons. The number below the element name is the atomic mass, also known as atomic weight. It represents the number of protons and neutrons in the nucleus of the atom. In carbon it is 12.001. The number 12.001 is not an even 12 because protons and neutrons are not exactly the same mass, and also because sometimes a bit of mass is lost in the process of binding. This is all very complicated, but you can always round the atomic mass number to its nearest integer value to find the total number of protons and neutrons in the standard, most prevalent atom of the element. There may be other forms of the atom called isotopes which are the same element but with different numbers of neutrons, and thus atomic masses. This difference in the number of neutrons was one of the challenges to early scientists trying to figure out the periodic table. To calculate out how many neutrons there are, we need to look at both numbers. The formula to use is: atomic mass – atomic number = number of neutrons In the case of carbon this is 12 – 6 = 6, which tells us that in carbon there are 6 electrons, 6 protons and 6 neutrons. Let’s look at another element, potassium (K). © 2013 Mission Science Workshop. All Rights Reserved worldwide. When linking to or using MSW content, images, or videos, credit MUST be included. It’s atomic number is 19, meaning there are 19 electrons and 19 protons in the atom. Using the formula above to calculate the number of neutrons in the nucleus, it tells us that there are 20 neutrons in potassium (39-­‐19=20). Links to k-­‐12 CA Content Standards: Grades k-­‐8 Standard Set Investigation and Experimentation: Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other strands, students should develop their own questions and perform investigations. Grades k-­‐12 Mathematical Reasoning: 1.0 Students make decisions about how to approach problems: 1.1 Analyze problems by identifying relationships, distinguishing relevant from irrelevant information, sequencing and prioritizing information, and observing patterns. 1.2 Determine when and how to break a problem into simpler parts. 2.0 Students use strategies, skills, and concepts in finding solutions: 1.1 Use estimation to verify the reasonableness of calculated results. 1.2 2.2 Apply strategies and results from simpler problems to more complex problems. 1.3 Use a variety of methods, such as words, numbers, symbols, charts, graphs, tables, diagrams, and models, to explain mathematical reasoning. 2.5 Indicate the relative advantages of exact and approximate solutions to problems and give answers to a specified degree of accuracy. 3.0 Students move beyond a particular problem by generalizing to other situations: 3.1 Evaluate the reasonableness of the solution in the context of the original situation. 3.2 Note the method of deriving the solution and demonstrate a conceptual understanding of the derivation by solving similar problems. 3.3 Develop generalizations of the results obtained and apply them in other circumstances. Grade 5 Standard Set 1. Physical Sciences: Elements and their combinations account for all the varied types of matter in the world. As a basis for understanding this concept: 1.a. Students know that during chemical reactions the atoms in the reactants rearrange to form products with different properties. 1.b. Students know all matter is made of atoms, which may combine to form molecules. 1.c. Students know metals have properties in common, such as high electrical and thermal conductivity. Some metals, such as aluminum (Al), iron (Fe), nickel (Ni), copper (Cu), silver (Ag), and gold (Au), are pure elements; others, such as steel and brass, are composed of a combination of elemental metals. 1.d. Students know that each element is made of one kind of atom and that the elements are organized in the periodic table by their chemical properties. © 2013 Mission Science Workshop. All Rights Reserved worldwide. When linking to or using MSW content, images, or videos, credit MUST be included. 1.h. Students know living organisms and most materials are composed of just a few elements. Grade 8 Standard Set 3. Structure and Matter: Each of the more than 100 elements of matter has distinct properties and a distinct atomic structure. All forms of matter are composed of one or more of the elements. As a basis for understanding this concept: 3.a. Students know the structure of the atom and know it is composed of protons, neutrons, and electrons. 3.b. Students know that compounds are formed by combining two or more different elements and that compounds have properties that are different from their constituent elements. 3.d. Students know the states of matter (solid, liquid, gas) depend on molecular motion. 3.e. Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently. 3.f. Students know how to use the periodic table to identify elements in simple compounds. © 2013 Mission Science Workshop. All Rights Reserved worldwide. When linking to or using MSW content, images, or videos, credit MUST be included.