Compounds

Which Elements form Ionic Bonds? The central idea (for the 51 st 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. CO 2 SO 4

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 – F 2, Cl 2, Br 2, 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 H H H NH 3

Diagram e - H N H H

Practice Exercise #1 Diagram the following Molecules and list what type of bond they have: –F 2 - CO 2 –Cl 2 - H 2 0 –O 2 - N 2 –SO - NO

Reading Covalent Bond Electronegativity Resonance Molecular Orbital Polar Covalent

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 naming Covalent Compounds Name the 1 st element by keeping its elemental name. Use a prefix only when there is more than one of that element. Name the 2 nd 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 tetrachloridetribromine octaoxide

Name the following compounds C3O2C3O2 BrF 3 P2O3P2O3 IF 6

Working with formulas 1.Determine the total number of atoms represented. 2.Total number of oxygen atoms represented in each compound. 3.Ionic or Covalent Compound? 1) NaCl7) Na 2 SO 4 2) CaCl 2 8) Ca(NO 3 ) 2 3) H 2 O9) Fe 2 (CO 3 ) 3 4) O 2 10) Co(C 2 H 3 O 2 ) 2 5) Cl 2 11) (CH 3 ) 3 N 6) C 6 H 12 O 6 12) LiH 2 PO 4

Working with more formulas 1.Determine the total number of atoms represented. 2.Total number of oxygen atoms represented in each compound. 3.Ionic or Covalent Compound? 1) 3 NaCl7) 9 (CH 3 ) 3 N 2) 7 H 2 O8) 10 Ca(NO 3 ) 2 3) 25 Cl 2 9) 8 C 6 H 4 (NO 2 ) 2 4) 11 Na 2 SO 4 10) 4 Fe 2 (CO 3 ) 3 5) 12 HCN11) 2 Hg 2 (NO 2 ) 2 6) 5 Co(C 2 H 3 O 2 ) 2 12) 6 LiH 2 PO 4