Notes

The student will:Accurately identify the characteristics of an Ionic Bond and a Covalent Bond

Demonstrate what causes a chemical bond

Valence ElectronIonic BondCovalent Bond

The electrons located on the outer energy level of each element.

The Number of valence electrons ranges from 1 – 8▪Atoms with 1 – 7 valence electrons are unstable and require bonding to make them complete▪Atoms with 8 valence electrons, The Noble Gases, are stable and therefore do not bond with any other elements.

A chemical bond between a metal and a nonmetal. It is when valence electrons are borrowed/taken from the metal to bring the outer energy electron level of the nonmetal up to 8

The metal “Donates” electrons to the non-metal

Metals donate, loan (lose) electrons while nonmetals borrow (gain) electronsEach metal loses electrons becoming a Positive (+) Ion

Each nonmetal gains electrons becoming a Negative (-) Ion

Have a high conductivity reading > 700 Micro-Siemens

Easily broken

A bond between two like atoms or a nonmetal and another nonmetal▪ The outer energy

level electrons are shared between the two atoms to make the valence complete at 8.

Are a very strong bond▪Are found in solid, liquid and gas form▪Bond like a chain link▪Low conductivity < 500 micro-Siemens

Most atoms by themselves are unstable All but group 18, The Noble Gases

They seek to complete their outer energy level to become stable

Low valence numbers (metals) lose electrons

High valence numbers (nonmetals) gain electrons

To become stable, atoms need to bond with other atomsMetals w/ NonmetalsNonmetals w/ NonmetalsSame atom w/ same atom

There are two types of chemical bonds▪Ionic Bond ▪Covalent Bond

Ionic Bond ▪Metals with nonmetals▪Na(1) + Cl(7) = NaCl(8) (valence numbers in parentheses)

Covalent Bond ▪Nonmetals w/ nonmetals▪Example:H(1) + H(1) + O(1) H2O (3)

(valence numbers in parentheses)

We can test for bond type by testing the conductivity of a chemical compound solutionThe chemicals in waterBy measuring Conductivity in Micro-Siemens

Remember:Bonding takes place to give atoms stability

Bonding allows for compounds to form

Remember:Atoms bonding with like atoms and nonmetals w/ nonmetals form Covalent Bonds

Remember:Metals bonding with non- metals form Ionic Bonds

Whew!Have a great day!