SJ #12 “Ionic Bonds”
Ch. 2-3 p. 59-64
 “Help a friend out…”
--listen as I read a story…
--it’s easy to figure out how to make both people happy!
ION: an atom or group of atoms that has become electrically
charged
*if an atom GIVES electrons, it becomes a POSITIVE (+) ION
*if an atom TAKES electrons, it becomes a NEGATIVE (-) ION
ELECTRON TRANSFER:
*remember, all atoms want a full outer shell to be stable (8 or 0 e-)
*atoms with 1, 2, or 3 val e- will always GIVE e- to get to zero
EX:
*To become STABLE,
Li will GIVE one e-
Li
*when it GIVES away a negative e-, it becomes a positive ion
Li has
+3 protons
-2 electrons
+1 charge
Li +1
Li +
*atoms with 5, 6, or 7 val e- will always TAKE e- to get to 8
EX:
*To become STABLE,
F will TAKE one e-
F
F has
+9 protons
-10 electrons
-1 charge
F -1  F p. 60 Ions and Their Charges
IONIC BOND: the attraction between two oppositely charged
IONS.
*opposite ions will balance out charges so Ionic Compounds
are ELECTRICALLY NEUTRAL.
*ONLY happens between a metal and a non-metal!
p. 61 “Exploring Ionic Bonds”
ionic bond
Li
F
+
-
Li F
+ table
-add ionic charges to periodic
lithium fluoride
POLYATOMIC IONS: what words do you know that start with
“poly-“?
“poly” = many (more than 1)
“atomic” = atoms
* group of atoms that acts like one atom
Examples: (pick any 2 to write down)
(CO3)2(OH)(NH4)+
(NO3)-
carbonate
hydroxide
ammonium
nitrate
NAMING IONIC COMPOUNDS
1. (+) ion, metal, always listed first
2. (-) ion, non-metal, always listed last
3. the name is ALWAYS 2 words
4. if the (-) ion is a single element (not
polyatomic) the ending of the compound
changes to “-ide”
O2-  MgO = magnesium
oxide
CaCl2 = calcium
chloride
5. polyatomic ion names do not change
EX:
Mg2+
PROPERTIES OF IONIC COMPOUNDS
1. crystal shape ex: halite (table salt)
*(+) and (-) ions form 3D crystal (p. 63)
-each ion is attracted to opposite charge
2. high melting point
*due to the strong attractions between ions
ex: salt M.P. = 801° C (1400°F)
*all SOLIDS at room temp
3. conduct electricity, but only when in solution!
*when dissolved, the ions let electrical
charges move through them.
*ex: salt water in a battery