Chapter 6 Chemical bonding
Do now Draw a web with pure substance as the main concepts Pure substance
3 different types of substances Molecular substances (only non metal atoms) Ionic compounds (metal and non metal ions) Metallic compounds (only metal atoms)
Molecular substances Composed of molecules in which elements share electrons. Elements: molecules are made of 1 type of atom. Ex. H2 ; O2 Compounds: molecules are made of 2 or more types of atoms. Ex. H2O ; NH3 ; CO2
Molecular formula Definition: shows the numbers and kinds of atoms present in a molecule of a compound. Ex. CO ( 1 molecule exist of 1 atom of carbon and 1 atom of oxygen) CH4 (1 molecule exist of 1 atom of carbon and 4 atoms of hydrogen)
Molecular compounds Just one type of atom? H2 Hydrogen N2 Nitrogen O2 Oxygen C Carbon S8 Sulfur
Molecular compounds (binary compounds) Prefixes are used to show how many atoms are present in each molecule. mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca (prefix + element root + ide)
Naming compounds (binary compounds) CO2 * No mono prefix is used on the first element Carbon dioxide Di means 2 oxygen atoms
Naming compounds (binary compounds) N2O PCl3
Monatomic vs. Diatomic Molecules Most molecules can be monatomic or diatomic Diatomic Molecule is a molecule consisting of two atoms There are 7 diatomic molecules (SUPER 7) – N2, O2, F2, Cl2, Br2, I2, H2 You can also remember them as: H2O2F2Br2I2N2Cl2
Bonding in molecules Covalent compounds form by sharing electrons to attain a noble gas electron configuration. Regardless of the type of bond, the Octet Rule still must be obeyed (8 valence electrons)
Single Covalent Bond A Single Covalent Bond consists of two atoms held together by sharing 1 pair of electrons (2 e-)
Double Covalent Bonds Sometimes atoms attain noble gas configuration by sharing 2 or 3 pairs of electrons A Double Covalent Bond is a bond that involves 2 shared pairs of electrons (4 e-)
Triple Covalent Bond A Triple Covalent Bond is a bond that involves 3 shared pairs of electrons (6 e-)