Integrated Chemistry 6-1-2 Explain why most atoms form chemical bonds. Most atoms form chemical bonds to obtain a lower potential energy. Many share or transfer electrons to get a noble gas configuration.

6-1-3 Describe ionic and covalent bonding. Ions form to lower the reactivity of an atom. Ionic bonding is when the attraction between many cations and anions hold atoms together.

Covalent bonding results from the sharing of electron pairs between two atoms. That is, when atoms share electrons, the mutual attraction between the electrons (electron clouds) and protons (the nucleus) hold the atoms together.

6-1-4 Explain why most chemical bonding is neither purely ionic nor purely covalent. In order for a bond to be totally ionic one atom would have to have an electronegativity of zero. (there aren’t any).

To have a purely covalent bond the electronegativity must be equal. (Only the electronegativity of atoms of the same element are identical, diatomic elements are purely covalent) 6-1-5 Classify bonding type according to electronegativity differences.

Differences in electronegativities reflect the character of bonding between elements. The electronegativity of the less- electronegative element is subtracted from that of the more- electronegative element. The greater the electronegativity difference, the more ionic is the bonding.

Covalent Bonding happens between atoms with an electronegativity difference of 1.7 or less. That is the bond has an ionic character of 50% or less. Electronegativity % Ionic Character Covalent Differences Bond Type 0 to 0.3 0% to 5% Non - Polar Over 0.3 up to 1.7 5% to 50% Polar Over 1.7 Greater than 50 % Ionic

Ionic Bonding occurs between atoms with an electronegativity difference of greater than 1.7. Sample Problem 6-1:p. 163. Close Section Review: p. 163. Go over 1-4.

Use electronegativity differences and Figure 6-2 to classify bonding between sulfur, S, and the following elements: hydrogen, H; cesium, Cs; and chlorine, Cl. In each pair, which atom will be more negative? From Figure 5-20 on page 151, we know that the electronegativity of sulfur is 2.5.The electronegativity of hydrogen is 2.1; the electronegativity of cesium is 0.7; and the electronegativity of chlorine is 3.0. In each pair, the atom with the larger electronegativity will be the more-negative atom.

Homework assignment is: read section 1 & complete Chapter Review: p. 195, 1-5 & 33-34.

Electronegativity - Simple to Understand Electron Dot Diagram - The Basics