Let´s RECAP
An element’s reactivity is determined by the number of valence electrons found
in an atom of the element.
In the periodic table, the number of valence electrons in each element increases
from left to right across each period.
Atoms tend to be stable and nonreactive if they have eight valence electrons.
The force of attraction that holds two atoms together is called a chemical bond.
1" an /of /found /atom/ of /valence /reactivity /the /number/ is
/the/ determined /by / element. / An /electrons /in /element’s
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2. " from / of /each /in /the /electrons /the/ right/ element
/increases /table, /periodic /number /period. /across /to /left /each/
valence /In "
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3. " eight /valence /they /to /be /Atoms /stable /and /if /have /tend/
electrons./nonreactive
"
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4. " of /together /called /attraction /bond. /atoms /two /chemical /
that /holds /is /The /a /force “
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What are Ions?
Li
NEUTRAL ATOM
# Protons___
# electrons ___
Atomic Number = _____
p+
e-
+
_
+
_
_
Li
+
Atom with an extra
POSITIVE charge
What are Ions?
F
p+
e-
+
_
+
NEUTRAL ATOM
# Protons___
# electrons ___
Atomic Number = _____
_
_
_
F
-
Atom with an extra
NEGATIVE charge
Li
+
Cation
Atom with an extra
POSITIVE charge
Anion
F
Element´s name
Lithium
Electron dot
diagram (Lewis
structure)
Type of element
(metal or non
metal)
Does it gain or lose
electrons? P.128
Aritmethic to
determine the
charge
Overall charge
v.e = charge = 3
3+
(# v.e) – 8 = (-3)
3-
Sodium
Beryllium
Magnesium
Aluminum
Nitrogen
Phosphorous
Oxygen
Sulfur
Chlorine
Bromine