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20.2 Types of bonds
Warm up
What is a chemical bond?
How do elements seek stability?
Objectives Describe ionic bonds and covalent
bondsIdentify the particles produced by
ionic bonding and by covalent bonding
Distinguish between a non-polar covalent and a polar covalent bond
Introduction Represent by drawing the way that Na and Cl form
Nacl.Represent by drawing the way H and O form H2O
Gain or loss electrons
Atoms and ionsAn atom that has lost or gained electrons is called
an ion.An ion is a charged particle that has either fewer
or more electrons than protons.
Group Outer e-
Lose or gain
Charge of ion
Atoms 1 1 Lose 1 +12 2 Lose 2 +213 3 Lose 3 +315 5 Gain 3 -316 6 gain2 -217 7 gain1 -1
Monoatomic and polyatomic ions
Ions can be two types:1- monoatomic ions (1 atom ion)2- polyatomic ions (more than one atom ion)
Polyatomic ion
What type of ion each of the following atoms will form?
1- potassium K (19)2- Magnesium Mg (12)3- Aluminum Al (13)4- Fluorine F (9)
A bond forms
Ionic bondWhat happens when you put Mg and Cl together
and allow them to react?Will they form a bond?How do you think they will form a bond? Can you draw an illustration that shows how a
bond is formed, if Mg (z=12) and Cl (z=17).What is the charge of the compound formed?
Think and concludeCan you predict what type of ion is formed when
one atom loses electron and the other gains electron?
Predict what type of elements lose electrons and what type of elements gain electrons?
When is an ionic bond formed?
Covalent bondsHow do elements reach stability if they don’t lose
or gain?Do they form ions?Predict how water molecules are formed.
Types of covalent bondsDraw the structure of:1- water2- carbon dioxide3- nitrogen gas
Three types of covalent bonds1- single covalent bond (2 electrons are shared between 2 atoms)2- double covalent bond (4 electrons are shared between 2 atoms)3- triple covalent bond (6 electrons are shared between 2 atoms)Give example about a molecule which contains single covalent bond, another molecule with a double covalent bond and a third molecule with a triple covalent bond.
Ionic bond VS covalent bondCompare between ionic and covalent bonds.
Unusual sharingElectrons are not always equally shared between
atoms in a covalent bond.The strength of the atom is related to the size of
the atom, charge of the nucleus, and the total number of electrons an atom contains
Equally or unequally sharingAtoms on the right side of the periodic table tend
to attract electrons more
Polar or non-polar moleculeIf atoms of a molecule share electrons equally: the molecule is non-polar
Ex: Cl2, O2, CO2
If atoms of a molecule share electrons unequally:
The molecule is polarEx: H2O, HCl, CHCl3, HF
Wrap up
Assignments
Section review questions. Page: 614