Atoms, Elements and Compounds

Atoms, Elements and Compounds

1. A molecule is a group of two or more kinds of atoms, made up of covalent bonds

2. Atoms, Elements and Compounds

   • Atoms and elements
     • Atoms are the basic unit that makes up an element
       • Isotopes
         • An isotope is an atom of an element with the same proton number, but a different nucleon number.
           • Radioisotopes : An isotope which has an unstable nucleus which breaks down in a short period of time, releasing energy
             • Medical Uses : Cobalt-60 for cancer treatment in radiotherapy
             • Industrial : Carbon-14 is used in carbon dating which helps archaeologists find the age of rocks, fossils
     • An element is a pure substance made up of only one type of atom
     • Sub Atomic Particles : This is how particles in an electron are arranged:
       • Proton- Positive charge. MASS= 1
       • Neutron - Neutral charge. MASS =1
       • Electron - Negative sarge. Found in electron shells. MASS= negligible
   • Atoms are arranged in shells - Determines reactivity.
     • Noble Gases - Full outer shells. Unreactive (cannot give or take electrons)

3. Compounds: A substance which consists of two or more elements,c chemically bonded together.

   • Cannot be separated by physical means

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