Dada Module

“Chemical Bonding” CHEMICAL BONDS

♥ A strong attractive force between atoms. Without these ties that bind, the universe would be nothing more than a mass chaos of individual atoms. A bond is formed when electrons from two atoms interact with each other and their atoms become joined. The electrons that interact with each other are VALENCE ELECTRONS, the ones that reside in the outermost electron shell of an atom. As you sit reading this sentence, billions of atoms surround you. When any two of them approach each other, their outermost electrons come into close contact. Recall that electrons are negatively charged particles, so a chance meeting between atoms usually results in the two repelling each other. Occasionally, however, atoms will stick together by forming a chemical bond.

2 main types of bonding: †Covalent Bonds †Ionic Bonds

COVALENT BOND →involve a complete sharing of electrons and occurs most commonly between atoms that have partially filled outer shells or energy levels. Thus if the atoms are similar in negativity then the electrons will be shared. Carbon forms covalent bonds. The electrons are in hybrid orbitals formed by the atoms involved as in this example: ethane. Diamond is strong because it involves a vast network of covalent bonds between the carbon atoms in the diamond.

IONIC BOND →occurs when one atom gains a valence electron from a different atom, forming a negative ion (ANION) and a positive ion (CATION), respectively. These oppositely charged ions are attracted to each other, forming an ionic bond. →arise from elements with low electro negativity(almost empty outer shells) reacting with elements with high electro negativity (mostly full outer shells). In this case there is a complete transfer of electrons. Previous Page

A well known example is table salt, sodium chloride. Sodium gives up its one outer shell electron completely to chlorine which needs only one electron to fill its shell. Thus, the attraction between these atoms is much like static electricity since opposite charges attract.

There is a third type of bonding, called METALLIC BONDING. As the name implies, metallic bonding usually occurs in metals, such as copper. A piece of copper metal has a certain arrangement of copper atoms. The valence electrons of these atoms are free to move about the piece of metal and are attracted to the

positive cores of copper, thus holding the atoms together. Essential to understanding all types of chemical bonding is realizing that all bonds use electron "glue." Every substance is made up of atoms, and all atoms are surrounded by the charged particles called electrons. Electrons in the outermost shell can and do bond with those of other atoms to create everything from quartz and quarters to plastic and pennies. In large part, the difference between materials as diverse as diamonds and pencils is how they're glued together.

These silver atoms are joined by metallic bonds.

“Introduction” One of the more important advances in chemistry was the understanding of the way atoms bond (join together) to form compounds. Atoms either share pairs of electrons between them (a covalent bond), or they transfer one or more electrons from one atom to another to form positive and negative ions, which are held together because of their opposite charge (the ionic bond). The electrons farthest away from the nucleus, the valence electrons, are the ones involved in bonding. Lewis symbols for elements show only the valence electrons possessed by a particular element. The valence shell becomes uniquely stable with 8 electrons. Many elements try to fill out the valence shell with 8 electrons by forming bonds with other atoms.

Questions: ♥ Atoms are the building blocks of all substances. But what is it that keeps atoms connected together? ♥What constitutes a chemical bond? ♥Why are chemical bonds important?

Answers:

●They are held together by CHEMICAL BONDS ●A bond is formed when electrons from two atoms interact with each other and their atoms become joined. ●The type of chemical bond that occurs in a molecule or substance in part defines its properties.

General Emilio Aguinaldo National High School Palico IV, Imus, Cavite

MODULE IN

CHEMISTRY (Types of Chemical Bonding)

Submitted by: Apacible, Criselda Anne Marie A. III- Deuteronomy

Submitted to: Mrs. De Leon

(Subject teacher)

Message I would like to dedicate this module to my beloved parents, sisters & brothers, relatives, teachers, classmates/friends & to those people close to my heart Especially to our father “GOD”.

Classmates, you’ve been a big part of my life. Thanks for all the times we’ve spend together. I will treasure all the memories.. And for our subject teacher in chemistry, Mrs. De Leon sorry for all the bad things that we did this school year. Thanks for being understanding and persistent… I hope you all do appreciate my work. God blessed us!!!