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Relating Nonmetallic Reactivity Trends to Atomic Structure
The reactivity of the nonmetals ties in well with the concept of electron affinity and the tendency to gain electrons. With nonmetals the greater the tendency to gain electrons, the more reactive it is. This argument should hold true whether we are talking about nonmetals within a family or within a period. As you go across a period, there is a greater nuclear charge and thus the electrons should be attracted more readily by elements that are further to the right and the tendency to gain electrons will increase. Thus the reactivity of the nonmetals should increase as you go from left to right across the periodic table, up to but not including the inert gases. |
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Distance Learning questions Clackamas Community College |
![Section of Periodic Table B-Xe [7PTnonm.JPG (18821 bytes)]](images/7PTnonm.JPG)
Nonmetals
usually react by gaining electrons, rather than by losing electrons like the metals do.
Let’s review how atomic structure affects the ability to gain electrons. From your
observations in the lab you know that as you go down a nonmetallic group in the periodic
table, the elements become less reactive. You also know that as you go down a group on the
periodic table, the number of energy levels is the most predominant factor. If an electron
comes into an atom that has a large number of energy levels, it will be further away from
the nucleus and not be attracted as strongly as it would be in a smaller atom with fewer
energy levels. For example, iodine is attracting an electron into its fifth energy level.
Bromine is attracting an electron into its fourth energy level. Bromine does a better job
of attracting electrons, and thus is more reactive, because it allows the new electron to
get closer to the nucleus where the force of attraction is stronger. Following this line
of reasoning and extending it to other atoms, we would expect chlorine to be even more
reactive and fluorine to be even more reactive still.
