11/2/2023 0 Comments Label carbon periodic table symbol![]() Mendeleev was a brilliant Russian scientist. The version of the Periodic Table that we use today was first proposed by Dmitri Ivanovich Mendeleev in 1872. Alchemists, experimenting with materials in their laboratory. Scientists wanted some way to classify the elements according to their properties that they were observing. They began to observe patterns and similarities in the way some groups of elements behaved and recorded these observations. Over time, our knowledge about the elements and their behaviour increased and scientists recognised the need to organise this information. We will find out more about elements in this chapter. But what do we mean by the word element? An element is a pure substance which cannot be broken down any further. These elements make up all the materials around us. Over time, many different elements were discovered by scientists all over the world. Scientists especially, wanted some understanding of all the different substances that they were working with. Mankind has been studying and experimenting with materials to try to understand matter for thousands of years. At least 3000 years ago, ancient people were already using embalming fluids (chemicals) obtained from plants to preserve the bodies of dead people and animals! An ancient Egyptian mummy that has been embalmed to preserve it. Early man discovered how to process natural ores into metals for ornaments, weapons and tools. People have been interested in science from the earliest times. It briefly explains what an element is, introduces Dmitri Mendeleev and his arrangement of the Periodic Table and also explains some of the concepts discussed later on in the chapter. The video in the above link is an entertaining and simple way to introduce learners to the subject matter of this chapter about elements and the Periodic Table. Sorting and classifying, identifying properties, comparingĪccessing and recalling information, reading, observing, identifying propertiesĪctivity: The regions of the Periodic TableĪccessing and recalling information, sorting and classifying, comparingĪccessing and recalling information, communicating, group work, making a poster Sorting and classifying, observing, identifying elements and properties, comparingĪctivity: Blitz revision of the properties of metals and non-metals 7.Ĥ.1 Arrangement of elements on the Periodic Table (2 hours)Īctivity: Comparing Mendeleev's table with the modern version of the Periodic TableĪccessing and recalling information, comparing,Īccessing and recalling information, observing,Ĥ.2 Properties of metals, semi-metals and non-metals (4 hours)Īctivity: What do some of the elements look like? This is considered too complex for learners in Gr. The detailed arrangement of the heavier atoms at the bottom of the table is not dealt with at this stage.However, as indicated in point 1 above, we have included some information on the atom and subatomic particles here in Gr. This is when they will formally learn that the atomic number indicates the number of protons in an atom. This is because the subatomic particles protons, neutrons and electrons will only be introduced later (in Gr. The meaning of the term atomic number (the number of protons in an atom of a given element). ![]() ![]() This same empirical approach has been used here to introduce the Periodic Table. Only later on when the model of the atom was further developed were scientists able to explain why elements are arranged as they are on the table. ![]() We are approaching it in the same way scientists did historically, namely, that they observed similarities and differences in elements and then used this information to arrange the elements in the table. However, the approach here has been to look at the Periodic Table as a means of classifying the elements. Therefore, some information on the atom has been included as an introduction. 8 in CAPS, whereas it was felt that some information on the atom was crucial at this stage to understand atomic numbers. Some important issues to note at this stage, namely: In reality the atomic number determines (rather than shows) the position of a given element on the table. We will deal with atomic number from the point of view that it shows the position of a given element on the Periodic Table. They will also learn that elements are arranged on the table according to their atomic numbers, starting with hydrogen (atomic number 1) at the top left hand corner and continuing from left to right across the table. They will learn about the main features of the Periodic Table and where the three categories of elements - metals, non-metals and semi-metals (also called the metalloids) - can be found. In this chapter learners are introduced to the Periodic Table of elements for the first time.
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