Post on 24-Feb-2016
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Types of Bonds
5.1Amole
Chemical Bonding When two or more atoms join a bond is
formed
It will not fall apart unless enough energy is added to break the bond
The type of bond determines certain properties of the compounds they create
Why do atoms bond? Octet Rule: Atoms tend to gain, lose, or share
electrons so as to have 8 electrons in their outermost shell (except for H and He)
Types of Bonds There are three main types of
bonds:
Ionic Bond
Covalent Bond
Metallic Bond
Learning Check: When two or more atoms join, a _________
forms.Bond
How many electrons do most atoms want in their outer shells?
8
What are the three types of bonds?Ionic, Covalent, and Metallic
IONIC BONDbond formed between
two ions by the transfer of electrons
Ionic Bonds Form between metals and nonmetals
Involves the transfer of electrons
The metal gives away electron(s) becoming a positive ion
The nonmetal gains electron(s) becoming a negative ion
The charged atoms are held together because the positive and negative forces are attracted to one another
Ionic bond – electron from Na is transferred to Cl, this causes a charge imbalance in each atom. The Na becomes (Na+) and the Cl becomes (Cl-), charged particles or ions.
Ionic Bonds: One Big Greedy Thief Dog!
Properties of Ionic Bonds Network solids
High melting and boiling points
Conduct electricity when melted
Many soluble in water but not in nonpolar liquid
Learning Check: When a bond is formed by the transfer of
electrons, a __________ bond is formed.Ionic
These bonds form between…Metals and nonmetals
The metals lose electrons to the nonmetals to create positive and negative ________.
Ions
COVALENT BOND
bond formed by the sharing
of electrons
Covalent Bonds Form between nonmetals
Involves the sharing of electrons
The nonmetals share one or more pairs of electrons to have a full octet
Two types: polar and nonpolar
Two Types: Determined by how electrons are
shared
Based on electronegativity
Shared evenly = Nonpolar
Shared unevenly = Polar
Non polar Covalent Bonds when electrons are shared equally H2 or Cl2
Oxygen Atom Oxygen Atom
Oxygen Molecule (O2)
Nonpolar Covalent Bonds: Evenly matched, but willing to share.
Polar Covalent Bonds when electrons are shared but
shared unequally H2O
Polar Covalent Bonds: Unevenly matched, but willing to share.
Properties of Covalent Bonds Gases, liquids, or solids
Low melting and boiling points
Poor electrical conductors in all phases
Many soluble in nonpolar liquids but not in water
Learning Check: When a bond is formed by the sharing of
electrons, a __________ bond is formed.Covalent
These bonds form between…Nonmetals
When atoms have different electronegativities, and share electrons unevenly, a ________ molecule is formed.
Polar
METALLIC BONDbond found in metals; holds
metal atoms together
very strongly
Metallic Bonds Form between metals
Involves the overlapping of outer energy levels
Attraction between one atom’s nucleus and a neighboring atom's electrons packs the atoms closely together
Allows electrons to move freely from one atom to another.
Metallic Bonds: Mellow dogs with plenty of bones to go
around.
Properties of Metallic Bonds Form alloys
Examples: steel, brass, bronze and pewter
Metals conduct electricity well do to the freedom of the electrons to move.
Metals are flexible because the atoms can slide past each other without their bonds breaking.
Identifying Types of Bonds
1. Look at the chemical formula2. Identify the elements in the compound3. Determine if the elements are metals or
nonmetals (using a periodic table)4. Metal – Metal = Metallic5. Metal – Nonmetal = Ionic6. Nonmetal -- Nonmetal = Covalent
1. Polar Covalent = different atoms/elements2. Nonpolar Covalent = same atoms/elements
Remember: Metals are on the left of the periodic table, and nonmetals are on the right.
Learning Check:Identify the type of bond present in each compound:
CH4
○ Carbon = Nonmetal○ Hydrogen = Nonmetal○ Covalent Bond (polar)
LiBr○ Lithium = Metal○ Bromine = Nonmetal○ Ionic Bond
FeCl3○ Iron = Metal○ Chlorine = Nonmetal○ Ionic Bond
O2
○ Oxygen = Nonmetal○ Oxygen = Nonmetal○ Covalent Bond (nonpolar)
Polyatomic Ions Compounds that contain polyatomic ions contain both ionic
and covalent bonds
Involves groups of covalently bonded atoms that have either lost or gained electrons.
Parenthesis group the atoms of a polyatomic ion to
remind you that they act as one ion.
Pg. 158 contains a list of many common Polyatomic Ions.
Learning Check:Identify the type of bond present in each compound:
MgCl2○ Magnesium = Metal○ Chlorine = Nonmetal○ Ionic Bond
NH4Cl○ Ammonium = Polyatomic Ion○ Chlorine = Nonmetal○ Both; Ionic and Covalent
NaOH○ Sodium = Metal○ Hydroxide = Polyatomic Ion○ Both; Ionic and Covalent
NO2
○ Nitrogen = Nonmetal○ Oxygen = Nonmetal○ Covalent Bond (polar)