Welcome to Chemistry Welcome to Chemistry Turn in electron configurationTurn in electron configuration Notes on BondingNotes on Bonding PracticePractice

Warm upWarm up

Write noble gas configuration for Write noble gas configuration for Cu and AgCu and Ag

Introduction to Introduction to Chemical BondingChemical Bonding

Chapter 6, Section Chapter 6, Section 11Get ready to take

notes

What is a bond?What is a bond?

A bond is an electrical attraction A bond is an electrical attraction between valence electrons and between valence electrons and protons of different atomsprotons of different atoms

Why bond?Why bond?

Nature likes things easy (ie. low Nature likes things easy (ie. low energy) and bonding causes energy) and bonding causes atoms to be more stable.atoms to be more stable.

2 Main types of bonds2 Main types of bonds

Covalent – electrons are shared Covalent – electrons are shared between nonmetalsbetween nonmetals

Ionic – electrons are transferred Ionic – electrons are transferred from cation to anionfrom cation to anion– Might want to refresh your memory Might want to refresh your memory

on electronegativity (p. 151)on electronegativity (p. 151)

What determines type What determines type of bond???of bond???

Electronegativity!Electronegativity!– Subtract the EN of Subtract the EN of

the 2 atoms, then . . .the 2 atoms, then . . . If difference is equal If difference is equal

to or more than 1.7 to or more than 1.7 = ionic= ionic

If difference is btwn If difference is btwn 0.3 & 1.7 = polar 0.3 & 1.7 = polar covalentcovalent

If difference is less If difference is less than 0.3 = non-polar than 0.3 = non-polar covalentcovalent

What were those What were those bonds again?bonds again? Ionic = electrons are transferredIonic = electrons are transferred Polar Covalent = electrons are shared, but Polar Covalent = electrons are shared, but

not equallynot equally Non-polar covalent = electrons are shared Non-polar covalent = electrons are shared

equallyequally

How ‘bout some How ‘bout some examples?examples? What type of bond would form What type of bond would form

between the following elements?between the following elements?– Hydrogen & SulfurHydrogen & Sulfur– Cesium & FluorineCesium & Fluorine– Carbon & chlorineCarbon & chlorine– 2 Oxygen atoms2 Oxygen atoms

PracticePractice S and HS and H

– 2.5-2.1=0.42.5-2.1=0.4– polar covalent (b)polar covalent (b)

Cs and FCs and F– 4.0-0.7=3.34.0-0.7=3.3– Ionic (c)Ionic (c)

C and ClC and Cl– 3.0-2.5=0.53.0-2.5=0.5– polar covalent (b)polar covalent (b)

PracticePractice Ca & ClCa & Cl

– 3.0-1.0=2.03.0-1.0=2.0– Ionic (c)Ionic (c)

O & OO & O– 3.5-3.5=0.03.5-3.5=0.0– nonpolar covalent (a)nonpolar covalent (a)

Cl and BrCl and Br– 3.0-2.8=0.23.0-2.8=0.2– nonpolar covalent (a)nonpolar covalent (a)