COVALENT BONDS 1 COVALENT BONDS Revised2.notebook February 21, - PowerPoint PPT Presentation

COVALENT BONDS Revised2.notebook February 21, 2013 COVALENT BONDS 1

COVALENT BONDS Revised2.notebook February 21, 2013 Learning Pre Post Targets 1 and Big Ideas Assess Assess 2 I can define, identify, and diagram covalent bonds I can determine the number of bonds formed by atoms when forming molecules. 2

COVALENT BONDS Revised2.notebook February 21, 2013 WHAT IS A COVALENT BOND? H N H N A covalent bond is when atoms share electrons. O O 3

COVALENT BONDS Revised2.notebook February 21, 2013 What type of elements form covalent bonds? • Covalent bonds often occur between nonmetals. The reason that atoms are able to bond is that the attractions are strong enough in both directions (protons for electrons) from both atoms. There must also be room for electrons in the outer energy level of both atoms. • In a covalent bond, both atoms t attract the two shared electrons a the same time. 4

COVALENT BONDS Revised2.notebook February 21, 2013 What groups will form covalent bonds? 5

COVALENT BONDS Revised2.notebook February 21, 2013 HOW DO COVALENT BONDS FORM? Let's take a closer look on how covalent bonds form by viewing this tutorial... TEACHERS DOMAIN COVALENT BONDING TUTORIAL 6

COVALENT BONDS Revised2.notebook February 21, 2013 Learning Targets 3 and 4 Pre Post Learning Target Big Ideas Assess Assess I can predict the formula for simple covalent molecules. I can correctly name covalent compounds. 7

COVALENT BONDS Revised2.notebook February 21, 2013 Bell work (Write the questions). 1. What is a covalent bond? 2. What elements are involved in forming covalent bonds? 3. When two nonmetal atoms are close together, how does the movement of electrons change? 4. What does the graph tell us about the potential energy of hydrogen atoms when they form a covalent bond? 8

COVALENT BONDS Revised2.notebook February 21, 2013 Lewis Dot Lewis Dot Diagrams help to determine how many pairs of electrons can be shared. For example, how many pairs of electrons can be shared in Fluorine gas? Nitrogen gas? F one unpaired electron = single bond N three unpaired electron = triple bond 9

COVALENT BONDS Revised2.notebook February 21, 2013 H H 10

COVALENT BONDS Revised2.notebook February 21, 2013 Single Bonds IN A SINGLE BOND, ATOMS SHARE A PAIR OF ELECTRONS. H 2 = Hydrogen Gas SHARES 2 ELECTRONS SHARES 2 ELECTRONS H H Forms a single bond 11

COVALENT BONDS Revised2.notebook February 21, 2013 Practice Illustrate the covalent bonds between the following atoms: Two Chlorine Atoms One Hydrogen and One Chlorine INCLUDE: • STRUCTURAL FORMULA • LEWIS DOT STRUCTURE SHOWING THE SHARING OF ELECTRONS • FORMULA • NAME OF THE COMPOUND 12

COVALENT BONDS Revised2.notebook February 21, 2013 Cl H Cl Cl Cl Cl Cl H 13

COVALENT BONDS Revised2.notebook February 21, 2013 ANSWERS WERE YOU RIGHT? Cl 2 HCl Cl Cl Cl H Cl Cl Cl H Hydrogen Chloride CHLORINE GAS 14

COVALENT BONDS Revised2.notebook February 21, 2013 O O 15

COVALENT BONDS Revised2.notebook February 21, 2013 DOUBLE BONDS In a double bond, atoms share 2 pairs of electrons. o 2= Oxygen Gas O O O O O O SHARES FOUR ELECTRONS R U O F S E R A H S S N O R T C E L E 16

COVALENT BONDS Revised2.notebook February 21, 2013 PRACTICE ILLUSTRATE THE COVALENT BONDS BETWEEN THE FOLLOWING: ONE CARBON AND TWO OXYGEN ATOMS ONE OXYGEN AND TWO HYDROGEN ATOMS INCLUDE: • STRUCTURAL FORMULA • LEWIS DOT STRUCTURE SHOWING THE SHARING OF ELECTRONS • FORMULA • NAME OF THE COMPOUND 17

COVALENT BONDS Revised2.notebook February 21, 2013 ANSWERS WERE YOU RIGHT?? CO 2 H 2 O O C O O H H C O O O H H WATER CARBON DIOXIDE 18

COVALENT BONDS Revised2.notebook February 21, 2013 COVALENT BONDS N 2 = Nitrogen Gas N N N N N N Forms a triple bond 19

COVALENT BONDS Revised2.notebook February 21, 2013 TRIPLE BONDS In a triple bond, atoms will share 3 pairs of electrons N 2 = Nitrogen Gas S H A SHARES 6 N R N E E ELECTRONS L S E 6 C T R O N S 20

COVALENT BONDS Revised2.notebook February 21, 2013 When are atoms the most stable? THE ATOMS IN A COVALENT BOND ARE MORE STABLE WHEN THEY ARE BONDED TOGETHER THAN WHEN THEY ARE APART THE LOWER THE ENERGY = THE MORE STABLE THE BOND 21

COVALENT BONDS Revised2.notebook February 21, 2013 Learning Targets 3 and 4 Pre Post Learning Target Big Ideas Assess Assess I can predict the formula for simple covalent molecules. I can correctly name covalent compounds. 22

COVALENT BONDS Revised2.notebook February 21, 2013 Bell Work Take 2 minutes to think about ionic bonds and covalent bonds and how they form. Write down all of the similarities and differences that you can between the two in your composition books. Now, "Give one and Get one" with 3 people at a different table and return to your seat. 23

COVALENT BONDS Revised2.notebook February 21, 2013 Learning Target 5 Pre Post Learning Target Big Ideas Assess Assess I can distinguish between ionic and covalent compounds. 24

COVALENT BONDS Revised2.notebook February 21, 2013 NAMING COMPOUNDS COVALENT COMPOUNDS ARE NAMED USING PREFIXES TO INDICATE THE NUMBER OF EACH TYPE OF ATOM PRESENT IN THE MOLECULE Mono = 1 CO 2 = Carbon Dioxide Di = 2 Cl 2 O = Dichlorine Monoxide Tri = 3 Tetra = 4 SO 3 = Sulfur Trioxide Penta =5 Hexa = 6 25

COVALENT BONDS Revised2.notebook February 21, 2013 Rules for Naming Binary Covalent Compounds Rule 1. The element with the lower group number is written first in the name; the element with the higher group number is written second in the name. Exception: when the compound contains oxygen and a halogen, the name of the halogen is the first word in the name. 26

COVALENT BONDS Revised2.notebook February 21, 2013 Rules for Naming Binary Covalent Compounds Rule 2. If both elements are in the same group, the element with the h igher period number is written first in the name. Rule 3. The second element in the name is named as if it were an anion, i.e., by adding the suffix ­ ide to the name of the element. Rule 4. Greek prefixes (see the Table provided at the bottom of this page) are used to indicate the number of atoms of each nonmetal element in the chemical formula for the compound. Exception: if the compound contains one atom of the element that is written first in the name, the prefix "mono­" is not used. 27

COVALENT BONDS Revised2.notebook February 21, 2013 Naming Binary Covalent Compounds Rule 4. Greek prefixes (see the Table provided at the prefix number indicated mono­ 1 bottom of this page) are used to indicate the number of di­ 2 tri­ 3 atoms of each nonmetal element in the chemical tetra­ 4 formula for the compound. penta­ 5 hexa­ 6 hepta­ 7 Exception: if the compound contains one atom of the octa­ 8 element that is written first in the name, the prefix nona­ 9 deca­ 10 "mono­" is not used. 28

COVALENT BONDS Revised2.notebook February 21, 2013 CAN YOU NAME THE FOLLOWING? • CO 2 Carbon Dioxide • S 2 O 3 Disulfur Trioxide Disulfur Trioxide • NO 2 Nitrogen Dioxide • CCl 4 Carbon Tetrachloride • SO Sulfur Monoxide • N 2 O 3 Dinitrogen Trioxide 29

COVALENT BONDS Revised2.notebook February 21, 2013 30

COVALENT BONDS Revised2.notebook February 21, 2013 31

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