Covalent Bonding

Covalent Bonds A bond between two(2) or more NON-METAL atoms Only have to worry about the small amount of non-metals on the right side of the staircase (no others) *Hydrogen is the only exception. Treat hydrogen as a non-metal* Electrons between the atoms are SHARED to form the bond No electrons are lost or gained, therefore no ions are formed This means you do NOT have to worry about charges at all! Unfortunately however, naming and formulas for covalent bonds is a completely different process

Naming and Formulas for Covalent Bonds Prefixes: 1 – “mono” 2 – “di” 3 – “tri” 4 – “tetra” 5 – “penta” 6 – “hexa” 7 – “hept” 8 – “oct” 9 – “non” 10 - “deca” Instead of using ions and charges to determine the names and numbers of atoms in formulas, when we are dealing covalent compounds we use prefixes  Prefixes indicate the number of atoms in a covalent compound AND they are used in naming covalent compounds You will NOT need to memorize these this year.

Naming when given the formula Step 1: Begin by writing down the names of the elements involved in the correct order i.e.: P2O5 = phosphorus oxygen Step 2: Based on the number of each of the atoms involved, add in the correct prefix to the element names = diphosphorus pentoxygen Step 3: Change the ending of the last element to the suffix “ide” = diphosphorus pentoxide

Getting the formula when given the name Step 1: Find the symbol of the atoms involved on the periodic table i.e.: dinitrogen tribromide = N & Br Step 2: Write the symbols down beside each other in the correct order N Br Step 3: Determine the number of each element is needed from the prefixes and place the number as a subscript on the right side of the symbol N2Br3

Tricky Rules The prefix “mono” is only used on the element that is named second i.e.: CO Name = carbon monoxide Not monocarbon monoxide Do not reduce any of the subscripts in covalent formulas i.e.: C2H4 stays as C2H4, not CH2 Compounds that only have one particular element in them do not need to include the (1) subscript in the formula i.e.: Nitrogen monosulfide Formula = NS Not N1S1

Examples Give formulas for the following: Carbon dioxide CO2 Trintrogen hexabromide N3Br6 Diboron heptachloride B2Cl7 Give names for the following: N3I5 Trinitrogen pentaiodide SiF4 Silicon tetrafluoride SeCl Selenium monochloride