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IONS
When you hear/see the word “ATOM” you can always assume that it is referring to the element in it’s
NEUTRAL state
A NEUTRAL ATOM means that there are the SAME number of positively charged PROTONS as there are
negatively charged ELECTRONS (the two charges balance out to zero)
Example: Nitrogen has +7 charge (protons)
and -7 charge (electrons) = 0 charge
REMINDER
Atoms can gain or lose electronsThis causes them to become electrically
charged
IONS = electrically charged atoms that have gained or lost electrons
IONS
Atoms will either lose some electrons or gain some electrons to become more stable
The most stable state for an atom is with a full octet (8 electrons in its valence shell)
The Noble Gases are all stable octets. Other atoms will gain or lose electrons to be stable like their nearest noble gas is
WHY DO IONS OCCUR?
Metal atoms lose e- to form positively charged cations
Example: Na loses 1 electron to become the ion Na +
CATIONS
Metal ions (cations) tend to lose electrons to become more stable
Example: Na atom has + 11 protons
And - 11 electrons
= 0 electric charge
But that one electron in it’s outer shell makes it unstable, so it will get rid of it and have the inner full shell its new
valence shell
Example:
Na ion has + 11 protons
And - 10 electrons
= +1 electric charge
METAL IONS
SODIUM ATOM VS. ION
Sodium ATOM (above) vs Sodium ION (above)
Notice that the ATOM has the SAME number p+ and e- Notice that the ION has 1 LESS electron than protons
Non-metal atoms gain e- to form negatively charged anions
Example: Cl picks up 1 electron to become the ion Cl-
ANIONS
Non-metal ions (anions) tend to gain electrons to become more stableExample:
Cl atom has + 17 protons And -17 electrons
= 0 electric charge
But that one electron missing in it’s outer shell makes it unstable, so it will pick up one to make its valence shell
fullExample:
Cl ion has + 17 protons And -18 electrons
= -1 electric charge
NON-METAL IONS
CHLORINE ATOM VS. ION
Chorine ATOM (above) vs Chlorine ION (above)
Notice that the ATOM has the SAME number p+ and e- Notice that the ION has 1 MORE electron than protons
HOW TO WRITE/SHOW AN ION
To write/show an ion, surround the element symbol with brackets, and write the new charge just outside the brackets in the top right
Metals lose electrons. Electrons are negatively charged. Each negative electron a metal atom loses makes it that much more
positively charged (it gets less negative).
Non-metals gain electrons. Electrons are negatively charged. Each negative electron a non-metal gains makes it that much more negatively charged (it gets more negative).
CHARGES
Don’t worry, we will go over some together… right now!
QUESTIONS?