The relationships they form

When two elements are added together it creates a violent exothermic reaction.

When we bonded sodium and chloride it created the exothermic reaction and formed the white residue as we call table salt.

All ionic compounds are electronically neutral and are held together by bonds.

Ionic bonds are just one type of chemical bonds used with elements.

A coulombic force of attraction between ions of opposite charges

Think-Pair-Share

What do they mean by coulombic?

All salts are held together by ionic bonds

The structure of salts show that the attraction between ions extends beyond single cation and anion ions.

The ions are tightly packed together causing the common salt to have a crystal arrangement.

Think-Pair-Share

How many chloride anions surround each sodium cation? How does this number compare with the number of sodium cations that surround each chloride anion?

In sodium chloride structures, each ion is closes to six oppositely charged ions.

The net effect causing ionic bonding forming salts is the coulombic forces, the attraction or repulsion between two objects that have electric charges.

This is what holds the cluster of ions together forming the salts.

This also follows with other halides of sodium.

Halides are a salt that is composed of cations combined with anions of on he of halogen elements.

Think-Pair-Share

What are halogen elements? Once you find out which elements are halogens,

list them on your periodic table.

Comprised of simple anions, F-, Cl-, Br-, I-, and At-

Formed from group 17 elements.

The smallest crystal of table salt that we can see still holds billions and billions of Na+ and Cl- ions.

Creates a lattice. Crystal lattice is a repetitive geometric

arrangement of points in space about which atoms, ions, or molecules are arranged to form a crystal structure.

Each sodium cation is surrounded by six anions, which are surrounded by six cations, except at the edges.

The ions are less uniformly arranged.

The ionic formula represents the ratio between cations and anions in a compound.

Cannot just count ions, they have to be viewed in a chemical lab which have found that ionic compounds do not consist of molecules.

Salt ions form repeating patterns and are held in place by coulombic forces over repulsive coulombic forces.

Crystals of salts are made of simple repeating units that are cubic in shape.

The smallest repeating unit is a crystal lattice is a unit cell.

Although all ions have structures, they can sometimes be different.

It is easier to see 1:1 ions than ions that are 1:2, those ions were found under an X-Ray Crystallography.

The larger the element the more neighbors it can have meaning:The more anions the element can have to

be surrounded byEx. Cesium and Chloride vs. Sodium and

Chloride

Cesium is larger so more Chloride ions can surround it hence why there are eight ions surrounding it compared to Sodium which is smaller and only has six Chloride atoms that surrounds it.

Ionization Energy: The amount of energy needed to remove an outer electron from a specific atom or ion in its ground state and in the gas phase

Atoms always resist having their electrons removed so the ionization energies are always positive

Na(g) + 495 kJ/mol Na+(g)+ e- (g)

Electron affinity is the energy needed to put an extra electron onto a neutral atom

Cl(g) + e_(g) – 349 kJ/mol Cl_ (g)

When we add the equation to the equation of removing an electron from an Na atom we find that the electron transfer from sodium to a chlorine atom is an endothermic reaction. Energy is needed for this reaction to occur.

Na(g) + Cl(g) + 146 kJ/mol Na+(g) + Cl- (g)

http://www.youtube.com/watch?v=Mx5JJWI2aaw

Look at page 171 for reference to forming salt with energy

Lattice energy is the energy released when separated atoms, ions or molecules come together to form a crystal.

Without lattice energy there would be no ability for the spontaneous process of exothermic reactions and no bond would be formed.

Lattice energies are calculated by adding up all of the reactions

Generally the compounds with smaller ions or greater charge will have higher lattice energies.

Look at Lattice Energy Hand-Out

TPS

1.Using table trends, predict whether the lattice energy of CsCl is larger or smaller than that of RbCl?

2.Predict whether the lattice energy of BaO is larger or smaller than that of RaO?

Ionic Compounds are typically hard and brittleHard: The compound can resist a large

force applied to itBrittle: When the applied force is too strong

to resist, the crystal develops a fracture rather than a dent.

Salts generally melt and boil at high temperatures due to strong attractions between their ions.

Due to the strong bonds between ions it takes a considerable amount of energy to free them from their fixed locations, which must occur for the compound to melt.

Ionic salts generally do not conduct electricity

Due to the ions fixed placements there is no motion which lacks the ability to conduct electricity

When salts melt or dissolve the ions can move about allowing them to conduct electricity

Ions are good conductors of electricity in the liquid state and when dissolved in water