CHEMICAL BONDING
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Learn about the different types of chemical bonding - ionic and covalent - and how atoms gain, lose, or share electrons to form stable compounds. Discover the properties of ionic and covalent compounds, as well as the formation and naming of ions.
CHEMICAL BONDING
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CHEMICAL BONDING When atoms meet, they combine!
Bonding • Atoms are most stable when they have 8 valence electrons (The Octet Rule) • Atoms can gain, lose, or shareelectrons to get 8 total valence electrons • When atoms gain, lose, or share electrons they are bonding • There are two types of bonding: ionic and covalent
Ionic Bonding • Formed between metals and nonmetalsthrough a transfer of electrons • The metalslose valence electrons (+) • The nonmetalsgain valence electrons (-) • The positive and negative ions are then attracted to each other like magnets • Ionic compounds must have a balanced amount of + and - charge!
Family Patterns for Ion Formation • Group 1: LOSE 1 valence electron (+1) • Group 2: LOSE 2 valence electrons (+2) • Group 13: LOSE 3 valence electrons (+3) • Group 14: SHARE 4 valence electrons, but could be +4 or – 4 • Group 15: GAIN 3valence electrons (-3) • Group 16: GAIN 2 valence electrons (-2) • Group 17: Gain 1 valence electrons (-1)
Identify the following charges(find the group they are in first) • Lithium (Li) • Phosphorus (P) • Aluminum (Al) • Oxygen (O) • Bromine (Br) • Magnesium (Mg)
Ions and Bonding - Practice • Sodium • Who would sodium bond with? • Ca (metal, + ion) • K (metal, +ion) • Li (metal, +ion) • Cl (nonmetal, - ion)
Which Compound is Ionic? • CO2 • C6H12O6 • CH4 • MgCl2
Polyatomic Ions • Ions that are made of a group of atoms, but they act like one atom (treat them like one ion with one charge) • Examples: • Hydroxide: (OH)-1 Carbonate: (CO3)-2 • Phosphate: (PO4)-3 Ammonium: (NH4)+1 • Nitrate: (NO3)-1
Writing Ionic Formulas How do I write an ionic formula? 1. First find the charge on each Na+1 and S-2 2. Now, all you need to do is cross the charges over and write them as subscripts (but don’t worry about the signs). Na2S1 • The one (1) is “understood” so you don’t have to use it when you write it down. Na2S
Writing Ionic Formulas • Try the following: • Sodium and oxygen • Lithium and Sulfur • Magnesium and Chlorine
Naming Ionic Bonds • Start with the name of the positive ion. • Change the end of the negative ion to –ide • If the negative end is polyatomic, DO NOTchange its name • Example 1: Sodium + Chlorine = Sodium Chloride • Example 2: Lithium + Nitrate = Lithium Nitrate
Properties of Ionic Compounds • Stronger bonds • High melting and boiling points • Crystalline structures (has tight, repetitive pattern) • High conductivity
Covalent Bonding • Formed between two or more nonmetals • Also known as MOLECULAR BONDING • Two or more atoms share electrons so that each atom has eight valence electrons
Which is the covalent bond? • NaCl • KF • CO2 • MgS
Properties of Covalent Compounds • Weaker bonds • Lower melting and boiling points • Not good conductors
Extra Info: Organic Compounds • Any compound that contains Carbon • Examples: CO2, C6H12O6, CH4 • Decide for the following: H2O O2 CO NaCl