The Chemistry of LifeThe Chemistry of Life

The Nature of MatterThe Nature of Matter

Atoms!!!Atoms!!!

Building Block of ElementsBuilding Block of ElementsContains a nucleus = centerContains a nucleus = centerHas Energy Levels surrounding the Has Energy Levels surrounding the

outsideoutsideEach atom is distinct for each individual Each atom is distinct for each individual

elementelement

Atomic StructureAtomic Structure

The protons and neutrons make up a The protons and neutrons make up a concentrated core= concentrated core= NUCLEUSNUCLEUS

The electrons are in constant motion The electrons are in constant motion circling the nucleus near the speed of circling the nucleus near the speed of light!!light!!

Parts of the AtomParts of the Atom

ProtonsProtons: positive charge; nucleus: positive charge; nucleusNeutronsNeutrons: no charge; nucleus: no charge; nucleusElectronsElectrons: negative charge, around : negative charge, around

nucleus in levels or shellsnucleus in levels or shells

ElementsElements

Made of the same kind of atomsMade of the same kind of atomsCannot be broken down Cannot be broken down 90 elements occur naturally on earth90 elements occur naturally on earthThey can all be found on the PERIODIC They can all be found on the PERIODIC

TABLE.TABLE.

THE PERIODIC TABLETHE PERIODIC TABLE

Reading the Periodic TableReading the Periodic Table

Left to Right, Top to Bottom Left to Right, Top to Bottom All elements are representedAll elements are represented by symbolsby symbols*They increase in increments of 1 *They increase in increments of 1

*atomic number= # of protons*atomic number= # of protons

*atomic mass= protons + neutrons*atomic mass= protons + neutrons

Consider The Following…Consider The Following…

Atomic # Atomic MassAtomic # Atomic Mass

2727 58.9 58.9

CoCo Element Element CobaltCobalt AtomicAtomic

NameName SymbolSymbol

What is an Isotope?What is an Isotope?

Atoms of the same element that have Atoms of the same element that have different numbers of NEUTRONS.different numbers of NEUTRONS.

The same elements will ALWAYS have The same elements will ALWAYS have the same number of protons.the same number of protons.

Ex: Carbon 12 and Carbon 14 Ex: Carbon 12 and Carbon 14

Find The Difference!Find The Difference!

http://web.visionlearning.com/custom/chemistry/animations/CHE1.3-an-isotopes.shtml

Note and explain the difference between the Note and explain the difference between the atoms shown!atoms shown!

Link courtesy of vision learning!Link courtesy of vision learning!

What is an Ion???What is an Ion???

An atom that has either lost or gained an An atom that has either lost or gained an electron from it’s outer most shell and taken on a electron from it’s outer most shell and taken on a chargecharge

Valence ShellValence Shell = Outer Most Shell = Outer Most Shell

+ = loss of an electron+ = loss of an electron - = gain of an electron- = gain of an electron

Ex: NaEx: Na++, Ca , Ca 2+2+ , Cl , Cl --

CompoundsCompounds

Two or more elements Two or more elements bondedbonded together togetherAlmost all substances in “nature” occur as Almost all substances in “nature” occur as

compoundscompoundsWhen elements combine to make When elements combine to make

compounds, they LOSE their original compounds, they LOSE their original properties.properties.

Ex: HEx: H2O, COO, CO2, and HCl , and HCl

Types of BondsTypes of Bonds

BondingBonding= 2 or more elements either = 2 or more elements either sharing or stealing sharing or stealing electronselectrons

Takes place in the OUTER MOST energy Takes place in the OUTER MOST energy levellevel

Who you bond with depends on the number Who you bond with depends on the number of electron vacancies in the valence shellof electron vacancies in the valence shell

Rules of Molecular BondingRules of Molecular Bonding

1.1. All atoms want to achieve STABILITY.All atoms want to achieve STABILITY.

2.2. Stability = FULL Valence ShellStability = FULL Valence Shell

3.3. However many electrons you need or However many electrons you need or can give away determines “who” you can give away determines “who” you bond with.bond with.

COVALENT BONDSCOVALENT BONDS formed when 2 atoms formed when 2 atoms shareshare electrons in electrons in

the outer most energy level forming a the outer most energy level forming a molecule with NO CHARGEmolecule with NO CHARGE

Classic Example: Water!!!Classic Example: Water!!!

IONIC BONDSIONIC BONDS

2 2 oppositelyoppositely charged ions attract each charged ions attract each other, forming a neutral bond (canceling other, forming a neutral bond (canceling each other out)each other out)

Classic Example: Sodium ChlorideClassic Example: Sodium Chloride

= Table Salt= Table Salt

For ExampleFor Example

Chlorine= 17 electronsChlorine= 17 electrons

2-first shell 8-second shell 2-first shell 8-second shell 7-third shell 7-third shell (holds 8)(holds 8)

so, Cl needs one more e- to be stableso, Cl needs one more e- to be stable

SODIUMSODIUM

Na has 11 e-, which means…Na has 11 e-, which means…

2 first shell 8 second shell2 first shell 8 second shell

only 1 in third shell (holds eight)only 1 in third shell (holds eight)

So, Na needs to LOSE one e-!!!So, Na needs to LOSE one e-!!!

Why Do They Bond?Why Do They Bond?