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'''Electronegativity''' is a measure of how strongly an [[atom]] in a [[molecule]] rejects extra [[electron]]s away from itself. This occurs because an atom has a positively charged centre (made up of [[proton]]s and [[neutron]]s) which is continuously orbited by electrons. Outside electrons are rejected because the charge distribution of an atom can be thought of as a positive centre surrounded by negativity. This negativity rejects any outside electrons (which also have a negative charge). Electronegativity increases as the number of electrons and orbital shells around the [[nucleus]] increases; they shield the outside electrons from the postive nucleus, which attacts them, making their rejection easier.<ref>Salters-Nuffield Salter's Advanced Chemistry: Chemical Ideas' - 2003</ref>  Generally, electronegativity increases across a horizontal row of the [[Periodic table of the elements|periodic table]], as well as up a vertical column.<ref>Solomon's Organic Chemistry, Fifth Edition, 1992</ref>  [[Fluorine]], a member of the Halogen group of elements, is the most electronegative known element.  A group of elements is a vertical column, and the Halogens are group 17.  Group 18, the Noble gases, are the most unreactive elements known.  This is due to the fact that they have a complete octet of electrons in their valence shell.   

'''Electronegativity''' is a measure of how strongly an [[atom]] in a [[molecule]] rejects extra [[electron]]s away from itself. This occurs because an atom has a positively charged centre (made up of [[proton]]s and [[neutron]]s) which is continuously orbited by electrons. Outside electrons are rejected because the charge distribution of an atom can be thought of as a positive centre surrounded by negativity. This negativity rejects any outside electrons (which also have a negative charge). Electronegativity increases as the number of electrons and orbital shells around the [[nucleus]] increases; they shield the outside electrons from the positive nucleus, which attacts them, making their rejection easier.<ref>Salters-Nuffield Salter's Advanced Chemistry: Chemical Ideas' - 2003</ref>  Generally, electronegativity increases across a horizontal row of the [[Periodic table of the elements|periodic table]], as well as up a vertical column.<ref>Solomon's Organic Chemistry, Fifth Edition, 1992</ref>  [[Fluorine]], a member of the Halogen group of elements, is the most electronegative known element.  A group of elements is a vertical column, and the Halogens are group 17.  Group 18, the Noble gases, are the most unreactive elements known.  This is due to the fact that they have a complete octet of electrons in their valence shell.   

==References==

==References==