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Chemical Bonding. Chemical Bond. The attraction between atoms that holds them together and makes them function as a unit. Ionic Bonds. Ionic Bonds. An ionic bond is a transfer of electrons between a metal and a nonmetal. Electrons are completely transferred from one atom to another.
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Chemical Bond • The attraction between atoms that holds them together and makes them function as a unit.
Ionic Bonds • An ionic bond is a transfer of electrons between a metal and a nonmetal. • Electrons are completely transferred from one atom to another. • They either lose or gain electrons and form ions. • The atoms are bound together by the attraction between the opposite charges.
Types of Ions • The metal donates electrons and becomes positively charged-cation • The non metal gains electrons and becomes negatively charged-anion • Example
Writing Formulas 1. Write the symbols of each element. 2. Put their charge in their upper right corner. 3. Crisscross the numbers down (Not the charges). Example: Write the formula for Magnesium Chloride. Mg Cl Mg+2 Cl-1 Mg Cl
Writing Formulas Practice Write the formula for: • Aluminum Bromide • Calcium Oxide • Calcium Nitride • Sodium Chloride • Al Br • 2. Ca O • 3. Ca N • 4. Na Cl
Covalent Bonds • A covalent bond is the sharing of electrons between 2 nonmetals. • example • Both of the nonmetals want to gain electrons so they will share electrons to fill their orbitals. **A complete outer orbital has 8 electrons.**
Types of Covalent Bonds • Non-polar: an electron is shared equally between the atoms. • Electronegativity difference: 0-0.3 • Ex: H2 • Polar: an electron is more attracted to one atom than to another. • Electronegativity difference: 0.3-1.7 • Ex: HCl
Electronegativity differences Non-polar bond: Ex: H2 2.1-2.1=0 Polar Bond: Ex: HCl 3.0-2.1=0.9
Lewis Dot for Covalent Bonds H2O • Can also be used to show bonding between atoms. • Electrons are placed between the atoms and are represented by a pair of dots or a dash. • Each dash represents one pair of electrons, or one bond. The structural formula shows a shared pair of electrons by a dashed line.
Drawing Covalent Bonds • Example: CH4 • Example: NH3
Multiple Bonds • A single covalent bond is formed for every pair of electrons shared between two atoms. • Some atoms can share multiple pairs of electrons, forming multiple covalent bonds. • Single bond- 1 pair of electrons • Double bond- 2 pair of electrons • Triple bond- 3 pair of electrons • example
Multiple Covalent Bonds Examples: • Oxygen has six valence electrons, so it needs two electrons to complete its octet. When two oxygen atoms bond, they share two pairs of electrons, forming two covalent bonds.
Extras • Diatomic molecule- is a molecule containing 2 identical atoms. • Examples: H2 N2 O2 F2 Cl2 Br2 I2 • Chemical Formula- represents the # of atoms of each element in a compound by using symbols and subscripts. • Example: H2O H=2 O=1 • Bonding Animation