Introduction

עמוד:7

Elements Elements * are substances that consist only of one kind of atom . For example , oxygen is an element because it consists only of oxygen atoms . Carbon dioxide , on the other hand , is not an element – it consists of molecules of one carbon atom and two oxygen atoms . Different elements consist of different atoms . Some commonly known elements are gold , iron , carbon and hydrogen . Elements are basic substances that cannot be broken down into simpler matter . Each element has unique properties that distinguish it from other elements . The structure of the elements The particles that make up the elements can be either atoms or molecules . These particles may be arranged in several ways . In chemical terminology , each element is assigned a chemical symbol * : one or more letters . The first letter in the symbol is always a capital letter , being the first letter of the element’s name . The following letter is a lowercase letter . Here are several common elements and their chemical symbols : Element – a substance consisting of only one kind of atom . Crystal – ( lattice ) – a gigantic , ordered structure in which the particles of a substance are bound together . Chemical symbol of an element – the symbol of an element , consisting of one or two letters from its name . Some elements are made up of atoms that are linked to one another in an ordered crystal * ( lattice ) structure . One example of such an element is carbon ( which occurs as diamond or graphite ) . Some elements are made up of molecules , in which two or more atoms of the same element are bound together . Such elements are , for example , oxygen and hydrogen . Some elements are made up of individual atoms , for example , helium and argon . Iron ( covered in rust ) Mercury Carbon ( in the form of coal )

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