Bonding and Chemical Reactions

Compounds and Molecules Chemical Bond: forces that hold atoms together in a compound. Chemical Structure: the arrangement of atoms in a substance Bond length: distance between nucleus of 2 atoms Bond Angle: angle the bonds between 3 or more atoms form

Chemical Structure compounds with networks are strong solids ex: diamond, quartz, many rocks networked compounds have melting and boiling points ex: salts, rocks, diamonds

Chemical Structure Some compounds are made of molecules ex: H2, O2, N2, CO2 are all gases with weak attraction hydrogen bonds are very strong

Bonding Atoms form bonds so each atom has 8 valence electrons. This is known as stable.

Ionic Bonding Ionic Bonds: between oppositely charged atoms; usually on opposite sides of the periodic table (nonmetal and a metal) transfer electrons form networks, not molecules conduct electricity

Covalent Bonds Covalent Bonds: share electrons; usually between 2 elements close on the periodic table (2 nonmetals) nonpolar covalent bond: e- shared equally polar covalent bond: e- shared unequally

Metallic Bonding “sea of electrons”: electrons can “float” freely between atoms; allows metals to conduct electricity well

Compound Names and Formulas Compounds have specific names so you can tell how many and what atoms are in the compound/molecule.

Ionic compounds MUST have a total charge of zero!! Ionic Naming Cations are just the name of the element Anions have -ide at the end of the element’s name Sodium Chloride Cation is ALWAYS FIRST Anion is ALWAYS LAST Ionic compounds MUST have a total charge of zero!! Na+1 + Cl-1 = NaCl = 0 charge!

Transition Metal Naming Transition metals show their charges as Roman Numerals because they can change charge!! FeO = Fe+2 + O-2 Iron (II) Oxide Fe2O3 = Fe+3 + O-2 Iron (III) Oxide

What is the formula for Lithium Oxide?

What is the name for CuCl2?

If you only have 1 cation, you don’t need a prefix! Covalent Naming To name covalent compounds, you must put a prefix in front of the element’s name. mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca- If you only have 1 cation, you don’t need a prefix!

What is the name of H2O?

Formulas Empirical Formula: smallest whole-number ratio of atoms in a compound Molecular Formula: how many atoms are in a molecule of a compound GLUCOSE Empirical Formula Molecular Formula CH2O C6H12O6

Chemical Reactions Rearrange atoms Involve changes in energy Exothermic: release energy (heat, fire, fizz, etc) Endothermic: absorb energy (drop in temp.)

methane and oxygen yield carbon dioxide and water Chemical Equations methane and oxygen yield carbon dioxide and water ___ CH4 + ___ O2 ___CO2 + ___ H2O Reactants Products

Balance the reaction. ___ Mg + ___ O2 ___MgO

Balance the reaction. ___ H2O2 ___H2O + ___ O2

Reaction Types Synthesis: A + B AB Decomposition: AB A + B Combustion: ALWAYS HAS O2 AS A REACTANT! AB + O2 AO + BO

Reaction Types Single-Replacement (single-displacement): AX + B A + BX Double-Replacement (double-displacement): AX + BY AY + BX