The Structure of an The Structure of an AtomAtom

Chapter 4.2Chapter 4.2

Warm-upWarm-up::KWL Chart - ATOMSKWL Chart - ATOMS

What I What I KnowKnow About AtomsAbout Atoms

What I Would What I Would Like to Like to LearnLearn About About Atoms Atoms

What I What I HaveHave LearnedLearned About AtomsAbout Atoms

Properties of Subatomic Properties of Subatomic ParticlesParticles

There are 3 types of subatomic There are 3 types of subatomic particles in an atomparticles in an atom– ProtonsProtons– ElectronsElectrons– NeutronsNeutrons

ProtonsProtons

POSITIVELY charged particle located POSITIVELY charged particle located in the nucleus of an atomin the nucleus of an atom

Each element contains at least 1 Each element contains at least 1 protonproton

Each proton has a charge of +1Each proton has a charge of +1 Rutherford discovered that the Rutherford discovered that the

amount of positive charge varies amount of positive charge varies among elementsamong elements

ElectronsElectrons

NEGATIVELY charged subatomic NEGATIVELY charged subatomic particle that is found in the space particle that is found in the space outside the nucleus outside the nucleus

Each electron has a charge of 1-Each electron has a charge of 1- Its mass is so small that it is not Its mass is so small that it is not

taken into consideration taken into consideration

NeutronsNeutrons

Neutral subatomic particle that is Neutral subatomic particle that is found in the nucleus of an atom.found in the nucleus of an atom.

Its mass is almost exactly equal to Its mass is almost exactly equal to that of a protonthat of a proton

Comparing Subatomic Comparing Subatomic ParticlesParticles

Protons, Neutrons, and Electrons can be Protons, Neutrons, and Electrons can be distinguished by mass, charge, and distinguished by mass, charge, and location in the atomlocation in the atom

ParticleParticle SymbSymbolol

RelativRelative e

ChargeCharge

Relative Relative MassMass

Actual Actual MassMass

ElectroElectronn

e-e- 1-1- 1/18361/1836 9.11x10-289.11x10-28

ProtonProton p+p+ 1+1+ 11 1.674x10-241.674x10-24

NeutroNeutronn

nn OO 11 1.675x10-241.675x10-24

Fun Facts About Atoms Fun Facts About Atoms

Atomic NumberAtomic Number

Atomic number of an element is Atomic number of an element is equal to the number of protons in the equal to the number of protons in the nucleus of that elementnucleus of that element– Atomic number = # protonsAtomic number = # protons

Atoms of different elements have Atoms of different elements have different numbers of protonsdifferent numbers of protons

Electrically Balanced AtomsElectrically Balanced Atoms

The number of protons in an atom is The number of protons in an atom is balanced by the number of electrons balanced by the number of electrons in the atom so that the atom does in the atom so that the atom does not carry a net chargenot carry a net charge

So, the atomic number also tells us So, the atomic number also tells us the # of electronsthe # of electrons

Mass NumberMass Number

Mass number = # protons + # Mass number = # protons + # neutrons (in the nucleus of neutrons (in the nucleus of

an atom)an atom)

Calculating the Number of Calculating the Number of NeutronsNeutrons

Number of Neutrons = Number of Neutrons =

Mass number – Atomic Mass number – Atomic NumberNumber

IsotopesIsotopes

Isotopes are atoms of the same Isotopes are atoms of the same element that have different numbers element that have different numbers of neutrons of neutrons

Isotopes of an element have the Isotopes of an element have the same atomic number, but different same atomic number, but different mass numbers because they have mass numbers because they have different numbers of neutronsdifferent numbers of neutrons

More About Isotopes..More About Isotopes..

Carbon IsotopesCarbon Isotopes