Chapter 9 – Covalent Compounds
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Chapter 9 – Covalent Compounds Covalent Compounds • Ionic compounds are formed when one element ________________________ _______________________________ another atom. Covalent Compounds • If elements ______________________, they share electrons or covalently bond. Covalent Compounds Covalent Compounds Covalent Bond – The attraction of a nucleus on one atom with the valence electrons of another. KEY FEATURES: results from ___________ electrons two elements must have _____________ electronegativities generally formed between ____________ Covalent Bonding Molecules Molecule – The structure formed when atoms bond covalently. Occurs when the bonded atoms are _____________ in energy than when the atoms are separate. Covalent Bonding Molecules Reminder: What do ionic compounds look like? Covalent Compounds Lewis Structures Use Lewis Dot structures to show what molecule would be formed when the following atoms bond. Key: Atoms share electrons in order to achieve a stable octet! H and F H and O O and O C and O Covalent Compounds Lewis Structures Use Lewis Dot structures to show what molecule would be formed when the following atoms bond. Key: Atoms share electrons in order to achieve a stable octet! N and H C and H N and N Covalent Compounds Bond Strength Bond Dissociation Energy - The amount of energy required to ______ a specific bond. • The ___________ pairs of electrons shared, the stronger the bond. • The ___________ ionic character a bond has, the stronger the bond. Covalent Compounds Bond Strength Ex. Which of the following is the strongest? NaCl or HCl Note: Bond length is an indicator of bond strength. – The stronger the bond, the ________ the bond. Ex. Which of the following is the strongest? Longest? H2 or O2 or N2 Covalent Compounds Naming Binary Molecular Compounds RULES: - See Separate Sheet 1) Use prefixes to indicate the number of atoms of each element. (omit mono- from first element) • Name the first element using the correct prefix. 2) Name the second element by using the stem (and correct prefix) and adding the ending “-ide” CO = carbon monoxide P2O5 = diphosphorus pentoxide Covalent Compounds Naming Binary Molecular Compounds Prefixes: 1 – mono 2 – di 3 – tri 4 – tetra 5- penta 6 – hexa 7- hepta 8- octa 9 – nona 10 - deca Covalent Compounds Naming Binary Molecular Compounds Practice: N2O N2O5 SF6 CCl4 BF3 H2O Covalent Compounds Naming Acids Naming Binary Acids Hydro(anion root)ic acid HF HCl HBr HI H2S Covalent Compounds Naming Acids Naming Oxyacids If the polyatomic ion contains -ate Æ (root)ic acid -ite Æ (root)ous acid H2SO4 H2SO3 H3PO4 H3PO3 HNO3 HNO2 NOTE: Oxyacids do NOT use the prefix “hydro-” Covalent Compounds Electronegativity and Polarity Electronegativity – • Electronegativity determines the type of bond that’s formed (i.e. how the electrons are redistributed). Summary – Structure/Bonding Covalent Bonding Ionic Bonding Summary - Properties Covalent Compounds 1. _______ m.p./b.p. (exist as _________ at room temp.) 2) _______ as solids 3) ___ soluble in water Ionic Compounds 1. _______ m.p./b.p. (exist as _________ at room temp.) 2) _______ as solids 3) ___ soluble in water Electronegativity and Polarity Molecular polarity deals with whether or not the entire molecule is polar i.e. has partially (-) and (+) ends (We won’t learn how to predict polarity.) Ionic/Covalent - Review Video - Making MgO and SO2 Notebook - Ionic vs. Covalent
