The electronic structure of an atom
is a description of how the electrons
are arranged.
It can be shown as number of
diagrams. (Preferably, diagrams)
The smallest amount of electrons (the dots or
crosses on the circle) you can have in a shell
(the circle) is 2 on the very first shell (which is
the smallest one)
When you have 8 electrons
(dots or crosses) on the
second shell (the circle
around the smallest one),
you need to start the third
shell. (a circle going around
the other circle.
The number of shells surrounding the
atom determine how reactive the atom is.
If there are 5 shells then it is really
reactive but if there is one shell then it
isn't really reactive or might not be
reactive at all.
If an atom GAINS electrons then it is a
negatively charged ion and if it
LOOSES an electron then it is
positively charged.
Remember the opposites.
If you GAIN 2, then you must put brackets
around the ion and put 2-