Chemical Bonding & the formation of Compounds

Slides:



Advertisements
Similar presentations
A look at ionic, covalent and metallic bonds
Advertisements

Types of chemical compounds
Chapter 7 Atoms & Bonding
Chapter 8: Elements and Chemical Bonds
Chemical Bonding and the Periodic Table There are three types of elements METALS: have luster, are good conductors of heat and electricity, typically solid.
Ions and Ionic Compounds
 Electrons in the highest occupied energy level of an element’s atoms  To find the number of valence electrons in an atom of a representative element,
Ionic Bonding and Ionic Compounds. Atoms and Ions  Atoms are the building blocks of matter (solids, liquids and gases).  For example:  Copper wire.
Chemical Bonding IONIC BONDS NOV. 21 Ionic Bonds  Characterized by a transfer of electrons  When electrons are transferred between atoms ions are produced.
CHAPTER INTRODUCTION Lesson 1Lesson 1Electrons and Energy Levels Lesson 2Lesson 2Compounds, Chemical Formulas, and Covalent Bonds Lesson 3Lesson 3Ionic.
4.2 How Elements Form Compounds
Chemical Bonds.
Valence Electrons are the electrons in the outermost shell of an atom. They are important in telling how the atom will react with certain chemicals. Like.
Physical Science Chapter 6 Chemical Bonds. Bonding Chapter 6 is about different types of atomic bonding Forces of attraction is the key to this bonding.
Chapter 7 Ionic and Metallic Bonding
What is a Chemical Bond? A chemical bond is a force holding two or more atoms together to form a molecule.
Two types of chemical bonds are Ionic Bonds and Covalent Bonds Chemical Bonding: Covalent Bonding.
Ionic and Covalent Bonding. » Atoms bond when their valence electrons interact ˃Atoms with full outermost energy levels are not reactive (Noble Gases)
The Octet Rule Noble gases are unlike any other group of elements on the periodic table because of their extreme stability. Each noble gas has eight valence.
Bonding.
Atoms and Bonding Chapter 5.
Chemical Bonding. Ionic Bonds Ionic bonds are made between metal and non-metal atoms Electrons are transferred from the metal atom to the non-metal atom.
Chapter 6 Covalent Compounds Section 1 – Covalent Bonds Sharing Electrons You learned that electrons are rearranged when an ionic bond forms. When this.
BONDING OF ELEMENTS Predict Why do elements bond? Why are valence electrons so important?
Combined elements –Compounds = unique properties from the elements that make them up. –NaCl for example Na = shiny, soft, silvery, metal that reacts violently.
Bonding Ionic Covalent (Metallic). How do atoms bond(join) together to form the millions of different compounds that make up the world? It all comes down.
Ionic & Molecular Compounds Chapter 3 Section 3.1.
Ionic Bonding Notes. Chemical Bonds 1. What is a chemical bond? A force that holds two atoms together 2. What is an ionic bond? An ionic bond is the attraction.
Opposites Attract What is an ion?
Chemical Bonds Regents Review Book: Chapter 4 Chapter 5 – Page 157.
Chemical Bonding An Introduction. Chemical Bonds A mutual electrical attraction between the nuclei and valence electrons of different atoms that bonds.
Dr. Marwa Eid 1 Chemical Bonds - attractive force that holds atoms or ions together - Chemical bonding are classified into 3 types ionic, covalent, metallic.
Physical Science Chapter 6 Chemical Bonds. Bonding Chapter 6 is about different types of atomic bonding Forces of attraction is the key to this bonding.
Module 4 Lesson 1 Ionic and Metallic Bonding. Have you ever wondered why… Metals can be easily formed into sheets? Metallic bonding.
Chapter 5 Atoms and Bonding.
Chapter 5: Soap. Section 5.1—Types of Bonds Objectives: distinguish between 4 types of bonding describe the characteristics of each type of bonding.
Bonding Types and Properties 1. Identify compounds as ionic or molecular (covalent) based on ionic compounds being the combination of metals with nonmetals.
Introduction to Bonding
BONDING AND CHEMICAL REACTIONS GAVS SHARED RESOURCES.
Chapter 7 and 8.  Valence electrons are responsible for the bonding between two atoms.
Ionic and Metallic Bonding. Why do elements bond with other elements? Elements combine chemically to increase the stability of their electrons Electrons.
Chemical Bonds. - Element: A substance that cannot be chemically converted into simpler substances; a substance in which all of the atoms have the same.
Notes 5-1 Atoms, Bonding and the Periodic Table Key Ideas: How is the reactivity of elements related to valence electrons in atoms? What does the periodic.
Chapter 4 Formation of Compounds
Unit 4 Bonding Notes.  All chemical compounds are held together by bonds  We will be learning about 3 types of bonds  Ionic, Covalent, and Metallic.
Bonding. Introduction to Bonding: Chemical bond: the force that holds two atoms together Bonds may be formed by the attraction of a cation to an anion.
Chapter 5 Atoms and Bonding. Valence Electrons and Bonding Valence electrons are those electrons that have the highest energy level and are held most.
WHY DO ATOMS BOND TOGETHER? ATOMS WANT TO ACHIEVE A STABLE ELECTRON CONFIGURATION (OR FULL OUTER SHELL OF VALENCE ELECTRONS).
CHAPTER 5: CHEMICAL BONDING Name:Prachayanee Chueamsuwanna Date: Oct. 19,2015.
Physical Science Chapter 6 Chemical Bonds. Bonding Chapter 6 is about different types of atomic bonding Forces of attraction is the key to this bonding.
Chemical Bonding Ionic and Covalent Bonds. What is a chemical bond? An attractive force that holds two atoms together Can form by – The attraction of.
Combining Atoms Through Chemical Reactions. The changing of one or more substances into other substances is called a chemical reaction. Chemical reactions.
1 Ionic and Metallic Bonding Ch Review What is a valence electron? –Electrons in the highest (outermost) occupied energy level Related to the group.
Chemical Bonding Ionic, Covalent, and Metallic bonding.
ATOMIC BONDING. INTRODUCTION OK, so we know that atoms can combine into compounds, and that when they do, they combine chemically during a chemical reaction.
Revision YEAR 11 ATOMIC STRUCTURE.  What is the atomic number of an element?  What is contained in the nucleus?  What does the word valence mean? 
Ionic Compounds. An element’s atoms need to acquire 8 valence electrons in order to be stable like a noble gas. (except for hydrogen and helium which.
Unit 3 Lesson 4 Ionic, Covalent, and Metallic Bonding Copyright © Houghton Mifflin Harcourt Publishing Company.
Unit 3 Lesson 4 Ionic, Covalent, and Metallic Bonding
Unit 3 Lesson 4 Ionic, Covalent, and Metallic Bonding
I. Introduction to Bonding
Unit 3 Lesson 4 Ionic, Covalent, and Metallic Bonding
Ionic, Covalent, and Metallic Bonding
Atomic Number = number of protons In atom
Part Two Reactions and Bonding.
Physical Science Chapter 5
Forming Chemical Bonds
Chemical Bonds & Reactions
I. Why Atoms Combine Chemical Formulas Chemical Bonds Stability
Chapters 7 and 8 – Bonding.
Presentation transcript:

Chemical Bonding & the formation of Compounds

Introduction There are only 118 or so elements listed on the periodic table, however there are obviously many more natural substances in nature.   This is because atoms can react with one another to form new substances called compounds. 

Compounds are different both chemically and physically from its parent atoms.  Example The element sodium is a silver-colored metal that reacts so violently with water that flames are produced when sodium gets wet.  The element chlorine is a greenish-colored gas that is so poisonous that it was used as a weapon in World War I.  However, when chemically bonded together, these two dangerous substances form the compound sodium chloride, a compound so safe that we eat it every day - common table salt!

Chemical Bonding chemical bonds are formed between atoms because electrons from the atoms interact with each other.  elements are most stable when they have full valence shell.  Atoms that do not have full valence shells bond together to share electrons and complete their valence shells. There are three main types of chemical bonds presented here, ionic, covalent & metallic.

Ionic Bonding In ionic bonding, electrons are completely transferred from one atom to another.  In the process of either losing or gaining negatively charged electrons, the reacting atoms form ions.  The oppositely charged ions are attracted to each other by electrostatic forces which are the basis of the ionic bond.  

An example For example, during the reaction of sodium with chlorine: sodium (on the left) loses its one valence electron to chlorine (on the right), resulting in a positively charged sodium ion (left) and a negatively charged chlorine ion (right).   

Formation of Sodium Chloride due to ionic bonding

Notice that when sodium loses its one valence electron it gets smaller in size, while chlorine grows larger when it gains an additional valence electron.  This is typical of the relative sizes of ions to atoms, positive ions tend to be smaller than their parent atoms while negative ions tend to be larger than their parent.  After the reaction takes place, the charged Na+ and Cl-  ions are held together by electrostatic forces, thus forming an ionic bond. 

Ionic compounds share many features in common: Ionic bonds form between metals and non-metals, Ionic compounds dissolve easily in water and other polar solvents, In solution, ionic compounds easily conduct electricity, Ionic compounds tend to form crystalline solids with high melting temperatures.

Covalent Bonding  The second major type of atomic bonding occurs when atoms share electrons.  As opposed to ionic bonding in which a complete transfer of electrons occurs, covalent bonding occurs when two (or more) elements share electrons. 

Covalent bonding occurs because the atoms in the compound have a similar tendency for electrons (generally to gain electrons).  This most commonly occurs when two non-metals bond together.   Because both of the non-metals will want to gain electrons, the elements involved will share electrons in an effort to fill their valence shells.

Formation of covalent bonds

Example A good example of a covalent bond is that which occurs between two hydrogen atoms.  Atoms of hydrogen (H) have one valence electron in their first electron shell.  Since the capacity of this shell is two electrons, each hydrogen atom will 'want' to pick up a second electron.   In an effort to pick up a second electron, hydrogen atoms will react with nearby hydrogen (H) atoms to form the compound H2.  Because the hydrogen compound is a combination of equally matched atoms, the atoms will share each others single electron, forming one covalent bond.  In this way, both atoms share the stability of a full valence shell. 

Unlike ionic compounds, covalent molecules exist as true molecules.  Because electrons are shared in covalent molecules, no full ionic charges are formed.  Thus covalent molecules are not  strongly attracted to one another.  As a result, covalent molecules move about freely and tend to exist as liquids or gases at room temperature.  

Metallic Bonding Metals have low ionization energies, thus they do not have a tight hold on their valence electrons.  These outer electrons easily move around, as they do not "belong" to any one atom, but are part of the whole metal crystal.  The negatively charged electrons act as a "cement" that hold the positively charged metal ions in their relatively fixed positions.

Metallic bonding….

The fact that the electrons flow easily helps to explain some of the characteristics of metals: - Metals are good conductors of heat and electricity. This is directly due to the mobility of the electrons. - The "cement" effect of the electrons determines the hardness of the metal.  Some metals are harder than others; the strength of the "cement" varies from metal to metal. -  Metals are lustrous.  This is due to the uniform way that the valence electrons of the metal absorb and re-emit light energy. - Metals are malleable (can be flattened) and ductile (can be drawn into wires) because of the way the metal cations and electrons can "flow" around each other, without breaking the crystal structure. *Metallic bonds are best characterized by the phrase "a sea of electrons"*

Glossary 1 Atom   The smallest unit of an element that retains the chemical properties of the element. Atoms can exist alone or in combinations with other atoms forming molecules. Chemical Bond   A link between atoms. See ionic bond and covalent bond. Chemical Reaction   A process in which atoms and molecules recombine by forming or breaking chemical bonds. Chemical reactions form new products that have different chemical properties than the initial reacting material. Compound   A material formed by the chemical combination of elements in defined proportions. Compounds can be chemically decomposed into simpler substances. Covalent Bond   A very strong chemical bond formed by the sharing of a pair of electrons. Multiple covalent bonds can be formed when multiple pairs of electrons are shared between atoms. Covalent bonds are generally characterized in two types, polar and non-polar covalent bonds.

Glossary 2 Covalent Molecule   A molecule held together by covalent bonds, that is, pairs of electrons shared between atoms. Covalent molecules are true chemical molecules whose interaction with other molecules is influenced by whether a polar molecule or non-polar molecule is formed Electron   A sub-atomic (ß link to atom) particle with a negative charge of 1.60 × 10-19 coulombs and a mass of 9.11 × 10-31 kg. Electrons are generally found in orbit around the nucleus of an atom, but may be gained or lost during ion formation. Element   One of less than 118 pure chemical substances. An element is a substance composed of atoms with identical atomic number. Force   The result of an interaction that is capable of changing the state of motion of an object. A 'push or pull' on an object resulting from its interaction with another object.  .

Glossary 3 Ion   An atom or molecule that has acquired an electrical charge by either gaining or losing electrons. A cation is an ion that has lost electrons and acquired a positive charge. An anion is an ion that has gained electrons and acquired a negative charge. Ionic Bond   A chemical bond characterized by electrostatic attraction between ions of opposite charge. The formation of an ionic bond involves a complete transfer of electrons between atoms, and can be predicted when one bonding atom has a much higher electronegativity than the other. Ionic Compound   A chemical compound held together by ionic bonds, that is, electrostatic attraction between positive and negative ions. Ionic compounds generally form ordered structures in which each cation is surrounded by several anions and vice versa. Thus ionic compounds commonly form complex lattices rather than true molecules. Parent   the material or source from which something is derived

Glossary 4 Solution   A mixture of more than one substance with properties that do not vary within the sample. Commonly used to describe a solid dissolved in a liquid, solutions of two or more gases, liquids, solid metals or other materials also exist. Also called a homogeneous mixture. Valence   The number of single bonds an atom can form, also measured as the number of hydrogen atoms that typically bond to an atom of an element. For example, in H2O, oxygen has a valence of two; in CH4, carbon has a valence of four. Valence Electron   Electrons that can be actively involved in chemical change; usually electrons in the shell with the highest value of n (electrons in the "outermost" shell of an atom). For example, sodium's ground state electron configuration is 1s2 2s2 2p6 3s1; the 3s electron is the only valence electron in the atom. Valence electrons determine the chemical properties of an atom and are the only electrons that participate in chemical bonding. Valence Shell   The outermost electron shell of an atom that contains electrons.

Acknowledgments 207.10.97.102/chemzone/lessons/ 03bonding/mleebonding/ionic_bonds.htm www.visionlearning.com/library/pop_glossary