Atomic Structure 10 1

8/3/2019 Atomic Structure 10 1

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Atomic StructureAtomic Structure


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Structure of the AtomStructure of the Atom

OBJECTIVE:OBJECTIVE:

DescribeDescribe

the structure ofthe structure of

atoms.atoms.


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Subatomic ParticlesSubatomic Particles

ParticleParticle ChargeCharge Mass (kg)Mass (kg) LocationLocation

ElectronElectron

(e(e--)) -1-1 9.11 x 109.11 x 10-31-31 shellsshells

aroundaroundnucleusnucleus

ProtonProton

(p(p

++

)) +1+1

1.67 x 101.67 x 10-27-27

NucleusNucleusNeutronNeutron

(n(noo)) 00 1.67 x 101.67 x 10-27-27 NucleusNucleus


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Distinguishing Among AtomsDistinguishing Among Atoms

OBJECTIVES:OBJECTIVES:

ExplainExp

lainwhat makeswhat makes

elementselements andand isotopesisotopes

different from each other.different from each other.


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Distinguishing Among AtomsDistinguishing Among Atoms

OBJECTIVES:OBJECTIVES:

CalculateCalculate

the number ofthe number of

neutrons in an atom.neutrons in an atom.


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Atomic NumberAtomic Number

Atoms are composed ofAtoms are composed ofidenticalidentical

protons, neutrons, and electronsprotons, neutrons, and electrons How then are atoms of one elementHow then are atoms of one element

different from another element?different from another element? Elements are different because theyElements are different because they

contain different numbers ofcontain different numbers ofPROTONSPROTONS

The The atomic numberatomic number of an element is of an element isthethe number of protonsnumber of p

rotons in the nucleusin the nucleus

# protons in an atom = # electrons# protons in an atom = # electrons


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Mass NumberMass Number

Mass number is the number of protons

and neutrons in the nucleus of an

isotope: Mass # = p+ + n0

NuclideNuclide pp++ nn00 ee-- Mass #Mass #

OxygenOxygen -- 1010

-- 3333 4242

-- 3131 1515

8 8 1818

Arsenic 75 33 75

Phosphorus 15 3116


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Proton number and massProton number and mass

numbernumber


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Complete SymbolsComplete Symbols

Contain the symbol of the element,Contain the symbol of the element,the mass number and the atomicthe mass number and the atomic

number.number.

X

Mass

number

Atomic

numberSubscript

Superscript


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SymbolsSymbols

s Find each of these:Find each of these:

a)a) number of protonsnumber of protons

b)b) number ofnumber ofneutronsneutrons

c)c) number ofnumber of

electronselectrons

d)d) Atomic numberAtomic number

e)e) Mass NumberMass Number

Br80

35


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SymbolsSymbols

s If an element has an atomicIf an element has an atomicnumber of 13 and a massnumber of 13 and a mass

number of 27, what is the:number of 27, what is the:

a)a) number of protonsnumber of protons

b)b) number of neutronsnumber of neutrons

c)c) number of electronsnumber of electrons

d)d) complete symbolcomplete symbol


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SymbolsSymbols

s If an element has 15If an element has 15electrons and 16 neutronselectrons and 16 neutrons

what is thewhat is thea)a) Atomic numberAtomic number

b)b) Mass numberMass numberc)c) number of protonsnumber of protons

d)d) complete symbolcomplete symbol


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IsotopesIsotopes

Atoms of the same elementAtoms of the same element cancan

have different numbers ofhave different numbers ofneutronsneutrons..Thus, different mass numbers.Thus, different mass numbers.These are calledThese are called isotopesisotopes..


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IsotopesIsotopes

Isotopes are atoms of the same elementhaving different masses, due to varying

numbers of neutrons.


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Naming IsotopesNaming Isotopes

We can also put the massWe can also put the massnumbernumberafterafter the name of thethe name of the

element:element:carbon-12carbon-12

carbon-14carbon-14uranium-235uranium-235


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Isotopes are atoms of the same element having

different masses, due to varying numbers of

neutrons.IsotopeIsotope ProtonsProtons ElectronsElectrons NeutronsNeutrons NucleusNucleus

Hydrogen1Hydrogen1

(protium)(protium) 11 11 00

Hydrogen-2Hydrogen-2

(deuterium)(deuterium) 11 11 11

Hydrogen-3Hydrogen-3(tritium)(tritium)

11 11 22


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IsotopesIsotopesElements

occur in

nature as

mixtures of

isotopes.

Isotopes are

atoms of the

same elementthat differ in

the number of

neutrons.


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Atomic Structure 10 1