5-3: Covalent BondsFind out how covalent bonds form and explore

the properties of molecular compounds.

Anticipatory Set

There are two ways to form bonds:1. Giving up or gaining electrons (Ionic Bonds)2. Sharing electrons (to be continued…)

California StandardsScience Standard 8.3.b: Students know that compounds

are formed by combining two or more different elements and that compounds have properties that are different from their constituent elements.

Science Standard 8.7.c: Students know substances can be classified by their properties, including their melting temperature, density, hardness, and thermal and electrical conductivity.

Reading Comprehension 8.2.7: (compare & contrast): Evaluate the unity, coherence, logic, internal consistency, and structural patterns of text.

Inputcovalent bond: the chemical bond formed

when two atoms share electrons.molecule: a neutral group of atoms joined by

covalent bonds.double bond: formed when two atoms

share two pairs of electrons.triple bond: formed when atoms share

three pairs of electrons.

Inputmolecular compound: a compound that is

composed of molecules.polar bond: a covalent bond in which

electrons are shared unequally.nonpolar bond: a covalent bond in which

electrons are shared equally.

Input & ModelingHow Covalent Bonds Form

The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus

for the shared pair of electrons.

Input & ModelingHow Covalent Bonds Form

Double and triple bonds can form when atoms share more

than one pair of electrons.

Input & ModelingHow Covalent Bonds Form

A carbon dioxide molecule has two double bonds.

Input & ModelingHow Covalent Bonds Form

A nitrogen molecule is an example of a triple bond.

Input & ModelingMolecular Compounds

Molecular compounds generally have lower melting points and boiling points than ionic compounds.

They do not conduct electric current when melted or dissolved in water.

Unequal Sharing of ElectronsUnequal sharing of electrons causes the

bonded atoms to have slight electrical charges.

Input & ModelingUnequal Sharing of Electrons

Fluorine forms a nonpolar bond with another fluorine atom.

Input & ModelingUnequal Sharing of Electrons

A carbon dioxide molecule is a nonpolar molecule because of its straight- line shape.

Input & ModelingUnequal Sharing of Electrons

In contrast, a water molecule is a polar molecule because of its bent shape.

Inputunity: refers to the way the ideas in a

piece of writing hang together.

coherence: the connection of ideas that makes them easy to follow.

Organization patterns:comparison and contrast: shows

similarities and differences

InputStandard 8.2.7: Compare & Contrast

Both carbon dioxide molecules (CO2) and water molecules (H2O) have polar bonds. Why then is carbon dioxide a nonpolar molecule while water is a polar molecule?

ModelingCompare & Contrast:

CO2 is nonpolar:

straight-line shape pulls electrons in

opposite directions.

H2O is polar: bent shape

pulls unequally; O-

and H+

Both have polar bonds

EXTENSION & HOMEWORK Write a detailed SUMMARY of the section and

complete the UNANSWERED QUESTIONS section of your notes.

Choose two of the remaining Depth & Complexity ICONS in your notes and explain how they relate to this section.

Complete the 5.3 Review and Reinforce worksheet.