View
223
Download
5
Category
Preview:
Citation preview
Chemical Bonding
How does bonding occur?
• Chemical bonding – the combining of atoms of elements to form new substances.
• The rules of chemical bonding are determined by the structure of the atom. The valence electrons determines if it will bond or not.
Bonding
• If an atom has 8 valence electrons it is stable and will not bond
• An atom with less than 8 valence electrons is unstable and will bond readily (easily)
• The ability to bond determines its ability to undergo chemical reactions
BondingNumber of valence: What happens:1, 2, 3 lose electrons5,6,7 gain electrons4 gain or lose8 unresponsive.. Nada.. nothing
1. Ionic bonding – involves a transfer of electrons. One atom gains and the other one loses (metal and non-metal)
Forms Ions – a charged atom (positive or negative).
2. Covalent bonding –They share electrons, rather than transfer. (Non-metal and non-metal), form molecules
3. Metallic bonding: metal and metal, electrons are able to fly off the energy levels
WHICH TYPE OF BOND IS THIS?
1. H + Cl =2. Sc + Hf =3. O + P =
Ionic Bonding
• Ionic bonding – involves a transfer of electrons. One atom gains and the other one loses.
• Ion – a charged atom (positive or negative).
• Example: Fluorine (F) has 7 valence electrons and to become stable, it gains 1 electron to fill its outermost level and becomes a negative ion.
Remember all atoms want 8 valence electronsMETALS AND NON METALS BOND
Ionic Bonding
Electron transfers to other atom
Covalent bonding• Covalent bonding – occurs between atoms that
have high ionization energy (a lot of valence electrons) and high electron affinity (attracts electrons)
• They share electrons, rather than transfer. “Co” means to share.
• Simplest example: Hydrogen H : H
COVALENT BONDING
Electrons are shared by both atoms
More about covalent bonds…
• Covalent bonds form molecules. • A molecule is the smallest particle of a
covalently bonded substance that shares all the properties of that substance.
NONMETAL AND NONMETAL
Bonds
Metallic Bonding • Metallic bonding – bond when the positive nuclei
are surrounded by mobile electrons. (all attracted at the same time). This allows the metals to be heat conductors.
• Referred to as the “sea of electrons”
• This is when the electrons are able to come off of their electron orbits and move freely.
METALS AND METALS
Electrons flying off energy levels
Vocabulary1. Chemical bonding – the combining of atoms of elements to form
new substances2. Ion – a charged atom (positive or negative).3. Ionization – the process of removing electrons to form ions. 4. The energy needed to remove the electrons is called ionization
energy.5. Electron affinity – the tendency of an atom to attract electrons.6. Polyatomic ion – when two elements bond first covalently then
through ionic bonding7. Oxidation number – the number of electrons an atom gains or
loses, or shares in a chemical bond.8. Diatomic elements – form bonds with atoms of the same
element.
Recommended