Presentation on theme: "Find out how covalent bonds form and explore the properties of molecular compounds."— Presentation transcript:
Find out how covalent bonds form and explore the properties of molecular compounds.
There are two ways to form bonds: 1.Giving up or gaining electrons (Ionic Bonds) 2.Sharing electrons (to be continued…)
Science 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.
covalent 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.
molecular 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.
How 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.
How Covalent Bonds Form Double and triple bonds can form when atoms share more than one pair of electrons.
How Covalent Bonds Form A carbon dioxide molecule has two double bonds.
How Covalent Bonds Form A nitrogen molecule is an example of a triple bond.
Molecular 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 Electrons Unequal sharing of electrons causes the bonded atoms to have slight electrical charges.
Unequal Sharing of Electrons Fluorine forms a nonpolar bond with another fluorine atom.
Unequal Sharing of Electrons A carbon dioxide molecule is a nonpolar molecule because of its straight- line shape.
Unequal Sharing of Electrons In contrast, a water molecule is a polar molecule because of its bent shape.
unity: 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
Standard 8.2.7: Compare & Contrast Both carbon dioxide molecules (CO 2 ) and water molecules (H 2 O) have polar bonds. Why then is carbon dioxide a nonpolar molecule while water is a polar molecule?
Compare & 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.