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Not that type of bonding!. BONDING!. CHEMICAL BONDING!. A chemical bond is the force that holds two or more atoms together. Only valence e - are involved in a chemical bond.
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Not that type of bonding! BONDING! CHEMICAL BONDING!
A chemical bond is the force that holds two or more atoms together. • Only valence e- are involved in a chemical bond. • Octet Rule: Atoms will gain, lose, or share electrons with another atom to have 8 valence electrons and be stable. Use the force! Believe in the force!
Two types of forces: • Intermolecular forces = an attractive force between two neighboring molecules. • Intramolecular forces = attractive force within one molecule. + - + -
Two types of chemical bonds: • Ionic Bonds = stronger bond made of metal and nonmetal formed when atom gains or loses e- to get full octet • Covalent Bonds = weaker bond made of two or more nonmetals formed when atom shares e- to get full octet
loss/gain e- share e- metals and nonmetals 2 or more nonmetals solid crystal lattice, hard, brittle liquid or gas high MP & BP lower MP & BP usually insoluble soluble (able to dissolve) conductive* not conductive
Common Examples • Salt – (NaCl) – is an ionic compound. How do we know this? • Na = metal (left of staircase) salt crystal • Cl = nonmetal(right of staircase) ionic compound • Salt’s Properties: • Solid crystal lattice • MP is 1473F; BP is 2669F (VERY HIGH) • Conductive • Soluble in water
Common Examples • Oxygen we breathe is actually O2 which is a covalent molecule. How do we know this? • O = nonmetal (right of staircase) covalentmolecule • Oxygen’s Properties: • gas • MP is -361F; BP is -297F (very low) • Non conductive
I EIGHT, I’m FULL, I’m HAPPY! Remember: Reactivity between atoms is based on getting a full octet – which ever way is best for that atom: either gaining e-, losing e-, or sharing e-.
Ionic Compounds Only Metal Atoms: lose e- to become positively charged cations ionic bond Nonmetal Atoms: gain e- to become negatively charged anions
When the positive metals and negative nonmetals come together, they form an ionic bond. Ionic bonds: attraction between oppositely charged ions (a metal and a nonmetal)
Oxidation Numbers tion # + + • The number of electrons an atom loses or gains to get a full octet creates the oxidation number for an element!
Note: It is easier to lose 1, 2, or 3 electrons than to gain 5, 6, or 7 electrons!
the group number = the number of valence e- = which helps you figure out the ox. # for group A elem. • THIS DOES NOT WORK FOR THE TRANSITION METALS OR INNER TRANSITION METALS!
Oxidation Numbers for the Group A Elements 3+ 1+ 2+ 1- 0 3- 2- NA
Write the ions formed for: Sr+2 • Strontium • Arsenic • Potassium • Iodine • Note: Only nonmetals change their names when bonding to have an ending of –ide. As-3 called arsenide in a compound K+1 or K+ I-1 or I- called iodide in a compound
Label the Compounds as Ionic or Covalent MgCl2 _________ CCl4 _________ H2 _________ Al2S3 _________ ionic metal + nonmetal covalent two nonmetals covalent two nonmetals ionic metal + nonmetal
Label the Compounds as Ionic or Covalent carbon dioxide ___________ potassium bromide ___________ aluminum iodide ___________ covalent two nonmetals ionic metal + nonmetal ionic metal + nonmetal