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עמוד:8
There are currently 118 known elements that have been observed and studied , of which about 90 are naturally-occurring elements . The rest are synthetic elements that can be synthesized in research laboratories , but they are unstable , meaning that they decay within a short period of time . All of the materials in the world are made of elemental atoms – the atoms of a single element or various combinations of elemental atoms . Elements are substances consisting of only one kind of atom . All of the materials in the world are made of the atoms of a single element or various combinations of elemental atoms . Question The following figures represent particles of various substances . Which of the figures represent elements ? Explain . Did you know ... Order does matter – diamonds and graphite Diamond is the hardest natural substance in the world ; it is transparent , shiny and does not conduct electricity . Graphite , found in pencils , is gray , soft , opaque and it does conduct electricity . Both of these substances consist only of carbon atoms , but their shapes and properties are completely different . How can these differences in their properties be explained ? The different arrangement of the atoms in diamond and in graphite explains their very different properties . Diamond Graphite
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