Compounds

Which Elements form Ionic Bonds?• The central idea (for the 51st time) is that

electrons, one or more, are transferred between the outer shells of adjacent atoms. This creates Ions/Charged Atoms.

• Metals and NonMetals. • Cation and anion.• Certain Elements may donate or receive

more than one electron. It can therefore bond with multiple elements, with different ratios

REVIEW

History

• Before 1913, all bonds were considered to be of the Ionic Type (called polar at the time).

• When doing Ion Beam analysis for CO it was found that the beam was evenly split between Carbon and Oxygen.

• Early work was done by Thompson and Rutherford.

Covalent Bonds

• The sharing of electrons in order to achieve a more STABLE electron structure.

• Atoms are held together closely by the strong bond.

• Atoms that have similar electronegativity values hold onto their electrons with the same amount of force. They therefore do not readily donate electrons.

Molecules

• The smallest amount of a covalent compound that still has the properties of that compound.

• The result of atoms held together by covalent bonds.

• CO2

• SO4

Different Types of Covalent Bond

• Single Bond– Two electrons shared between two atoms.

• Double Bond– Four electrons shared between two atoms.

• Triple Bond– Six shared electrons between two atoms.

Single Bonds

• Example: Halogens– F2, Cl2, Br2, etc.

• Take place when 2 electrons are shared between 2 atoms.– Two atoms of the same element bonded to

Itself.

Double Bonds

• Four Electrons shared between two atoms.

• Example: The Chalcogens

Triple Bonds

• Six electrons share between two atoms.

• Nitrogen is involved in many molecules with a triple bond.

Covalent Bond Diagrams

Nitrogen

Hydrogen

Covalent Bond Diagrams

N N

H

HH

H

NH3

Diagram

e-e-

H N H

H

Practice Exercise #1• Diagram the following Molecules and list

what type of bond they have:

– F2 - CO2

– Cl2 - H20

– O2 - N2

– SO - NO

Naming Covalent Compounds

Naming Simple (Binary)Covalent

Compounds

Prefixes

1 mono- 6 hexa-2 di- 7 hepta-3 tri- 8 octa-4 tetra- 9 nona-5 penta- 10 deca-

Rules for namingCovalent Compounds

• Name the 1st element by keeping its elemental name.Use a prefix only when there is more than one of that element.

• Name the 2nd element as if it were a negative ion. (ide)Always use a prefix.

Watch awkward pronunciations

Tetraoxide or Tetroxide

Carbon Mono-oxide or Carbon Monoxide

Write the following formulas

nitrogen dioxide tetraphosphorus heptasulfide

carbon tetrachloride tribromine octaoxide

Name the following compounds

C3O2 BrF3

P2O3 IF6