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 other electrons, the valence electrons can absorb and release energy.

Chemical bonds are the forces that hold particles of matter together.

Some elements do not usually form bonds. These are the elements in Group 18. The noble gases. They each have a complete outer energy level and are considered stable because of their electron configuration.

IonsMany atoms gain or lose electrons and end up with the same number of outer electrons as a noble gas. When a neutral atom loses or gains electrons, it becomes a charged particle

A charged particle is called an ion. In an ion the number of protons and the number of electrons are not equal.

If there are more protons than electrons the ion will have a positive charge. IF there are more electrons the ion will have a negative charge.

Usually metals lose electrons and non metals gain electrons.

When a neutral sodium atom loses one electron, it becomes a positive sodium ion.

11 protons10 electrons

The sodium ion has a charge of 1+.Na1+

Ionic bonding is perhaps the easiest of the three bond types to comprehend because it ties in with the idea that opposites attract. Specifically, opposite electric charges attract one another.

Remember that metallic atoms tend to lose electrons. When they do so, they become positively charged ions which are called cations.

Nonmetallic atoms tend to gain electrons to become negatively charged ions which are called anions.

These oppositely charged cations and anions are attracted to one another because of their opposite charges. That attraction is called an ionic bond. We often refer to the charge on the ion as the oxidation state of that element.

Potassium BromidePotassium is a metal, silvery-white in color. It easily decomposes when exposed to water, and it also catches fire easily during this reaction.

Bromide, a non-metal, is a liquid with reddish-brown color. As one of the examples of ionic bonds, the chemical bonding that occurs between bromide and potassium produces potassium bromide.

KBr has uses in veterinary medicine as a treatment for animals with epilepsy. It is also utilized in photographic plates and paper manufacturing.

1. How is an ion different from an atom?

2. What is an ionic bond?

3. What are some properties of ionic bonds?

4. Write the formulas for each:magnesium chloride calcium oxide lithium bromide   carbon monoxide

zinc chloride potassium iodide 

1. An ion is a charged particle, and atom is neutral.

2. An ionic bond is a force of attraction between two oppositely charged particles.

3. The bonds in an ionic bond are very strong. Ionic compounds are very stable, have high melting points, high boiling points, Usually they are brittle, and do not conduct electricity as solids, but will conduct when melted or dissolved in water.

4. Write the formulas for each:magnesium chloride calcium oxide lithium bromide   carbon monoxidezinc chloride potassium iodide 

MgCl  CaO  LiBr CO ZnCl2 KI 

Consider the elements lithium, sodium potassium and rubidium in Group 1. They all have one valance electron and all form an ion with a charge of 1+. Rubidium gives up its electron to form a positive ion much more easily than does any of the others. Potassium gives up its one electron easily than do the rest, and sodium gives up its electron more easily than lithium. Can you explain this?

Think about it and write your answer in your notebook......

Covalent bonding is what we call the strong attraction that holds together the atoms of nonmetallic elements. It is found in elements and in compounds. It is also found within the polyatomic ions. Essentially it is found in any material in which nonmetallic atoms are bonded together.

In covalent bonding, both atoms are trying to attract electrons--the same electrons. Thus, the electrons are shared tightly between the atoms. The force of attraction that each atom exerts on the shared electrons is what holds the two atoms together.

The shared electrons of a covalent bond can be represented using Lewis diagrams. The bond can be emphasized by using a line to "hold the atoms together." The electron dots that are not involved in the bond are sometimes shown and sometimes not shown.

What is the difference between the chemical bond that forms NaCl and Cl2?

Metallic Bonds

Most metals have one, two, or three electrons in their outer energy level. During many chemical reactions, metal atoms lose their outer electrons to other atoms, usually nonmetals.

The larger metals lose their outer electrons the most easily, because these electrons are farther away from the pull of the positively charged nucleus. A metal atom becomes stable, or nonreactive, when it has lost its outer electrons.

What kind of bonding is this?

The outer electrons in a metal atom are far from the nucleus and are held in place loosely.

In a metallic solid the atoms are so close together that their outer energy levels overlap. Because of these conditions, the outer electrons are able to move from one atom to another.

In a metallic solid, the outer electrons are thought of as belonging to the whole structure rather than to single atoms. This structure is called a network.

Red are electrons

Blue are metal atoms

A network of metal atoms

The metallic network is made up of positively charged metal ions with electrons all around them. The force of attraction that holds the network together is called a metallic bond.

The network is an arrangement of positive ions in a sea of electrons.

This freely moving sea of electrons explains why metals conduct electricity.

Electrons that enter one end of a wire flow through the wire and out the other end.

Because there are no individual bonds, the ions and electrons can be moved into new positions without cracking or breaking the metal object. The sea of electrons and ions is rearranged each time a metal is forced into a new shape.

The metallic bond also explains why metals are malleable and ductile.

Ionic Bondsmetal to non metal atomselectrons are lost and gained

Covalent Bondsnonmetal to nonmetalelectrons are shared

Metallic Bonds

metal to metal atoms

sea of electrons, electrons belong to the entire network