AtomicStructure

Define the atomStructure of the

Nuclear AtomDistinguish

between atoms

In groups of 7 you will research the In groups of 7 you will research the following scientists’ ideas and following scientists’ ideas and contributions to the atomic model. contributions to the atomic model.

1. 1. John DaltonJohn Dalton, 2. , 2. DemocritusDemocritus, 3. , 3. J.J J.J ThomsonThomson, 4. , 4. Ernest RutherfordErnest Rutherford, 5. , 5. Robert Robert MillikanMillikan,,

6. 6. Eugen GoldsteinEugen Goldstein, 7. , 7. James ChadwickJames Chadwick You will present your findings to the classYou will present your findings to the class

Early Models of the Early Models of the AtomAtom

Subatomicparticle

charge symbol location Mass(mass of proton=1)

What are the 3 kinds of subatomic What are the 3 kinds of subatomic particles?particles?

? Charge? Location? Symbol

protonsneutrons

electrons

The Number of protons (atomic number)The Number of protons (atomic number) Atoms are electrically neutral; therefore the number of Atoms are electrically neutral; therefore the number of

protons (+) must equal the number of electrons (-)protons (+) must equal the number of electrons (-)

What makes one element differ from What makes one element differ from another?another?

element Atomic # protons electrons

K 19 19

5

S 16

Try these!

6

23

V50.941

symbol

Average Atomic mass

Atomic number

Find the difference between the mass Find the difference between the mass number and atomic numbernumber and atomic number

How do you find the # of How do you find the # of neutrons?neutrons?

14

Si28.086

?Atomic number# of protons

# of electrons

?Average atomic massRound this for mass number

Atomic number =

Mass number =

Number of neutrons=

1.Write the symbol, place the atomic number 1.Write the symbol, place the atomic number as the subscript and the mass number as as the subscript and the mass number as the superscript to the left of the symbol.the superscript to the left of the symbol.

Shorthand notationShorthand notation

14

Si28.086

2814 Si

2. Also can be written with the name of the symbol and the mass number

Silicon-28

element Atomic #

Mass # protons electrons

neutrons

Beryllium 4 9

Neon 10 20

Sodium 11 23

practicepractice

A.

B. How many neutrons are in each atom?

168

O 3216 S 108

47 Ag

p+ = e- = n0=

p+ = e- = no =

p+ = e- = no =

element Atomic #

Mass # protons electrons

neutrons

Radon 86 ? ? ? 136

Iodine ? ? 53 ? 74

? ? 128 ? 52 ?

bismuth ? ? 83 ? 126

Remember!!Remember!!Atomic # = protons = electronsAtomic # = protons = electrons

Mass # = Protons + NeutronsMass # = Protons + Neutrons

Neutrons = Mass # - ProtonsNeutrons = Mass # - Protons

Protons = Mass # - NeutronsProtons = Mass # - Neutrons

Tellurium

Atoms that have the same number of Atoms that have the same number of protons, but different numbers of protons, but different numbers of neutrons, therefore having different neutrons, therefore having different mass numbersmass numbers

Isotopes are chemically alike due to Isotopes are chemically alike due to the # of protons and electronsthe # of protons and electrons

IsotopesIsotopes

•There are 3 known isotopes of hydrogen.•Each isotope has one proton•Most common = hydrogen-1 or H•2nd isotope has one neutron (mass # of 2) = _____________or hydrogen-2 or H•3rd isotope has 2 neutrons (mass # of 3) = •___________or hydrogen-3 or H

11

21

31

1.1. Three isotopes of oxygen are oxygen-Three isotopes of oxygen are oxygen-16, oxygen-17, oxygen-18. Write the 16, oxygen-17, oxygen-18. Write the symbol for each, including the atomic symbol for each, including the atomic number and mass number.number and mass number.

1.1. Three isotopes of chromium are Three isotopes of chromium are chromium-50, chromium-52, and chromium-50, chromium-52, and chromium-53. How many neutrons are chromium-53. How many neutrons are in each isotope, given that chromium in each isotope, given that chromium has an atomic number of 24?has an atomic number of 24?

PracticePractice

168 O 17

8 O 188 O

Chromium-50 = ____ neutrons

Chromium-52 = ____neutrons

Chromium-53 = ____ neutrons

1.1. Research common Research common isotopes (radioistopes)isotopes (radioistopes)

2.2. Create a display over Create a display over commonly used isotopes.commonly used isotopes.

3.3. Include the isotope and its Include the isotope and its useuse

4.4. Also may include pictures, Also may include pictures, etc.etc.

Extra CreditExtra Credit

Atomic mass unit- (amu)-

Atomic mass=

Atomic Mass

Calculating the atomic massMultiply the mass of each isotope by the natural abundance, expressed as a decimal, and then add the products

Element X has 2 natural isotopes. The isotope with a Element X has 2 natural isotopes. The isotope with a mass of 10.012 amu (mass of 10.012 amu (1010X) has a relative abundance of X) has a relative abundance of 19.91%. The isotope with a mass of 11.009 amu (19.91%. The isotope with a mass of 11.009 amu (1111X) has X) has a relative abundance of 80.09%. Calculate the atomic a relative abundance of 80.09%. Calculate the atomic mass of this elementmass of this element

knownsknowns**isotope 10Xisotope 10X

mass = 10.012 amumass = 10.012 amu

rel. abun= 19.91% or rel. abun= 19.91% or 0.1991 0.1991

*Isotope *Isotope 1111X:X:

mass = 11.009 amumass = 11.009 amu

rel. abun.= 80.09% or rel. abun.= 80.09% or 0.80090.8009 unknownsunknowns

* Atomic mass of element X ?* Atomic mass of element X ?

Practice

Calculate

For 10X: 10.012 amu x 0.01991= 1.993 amu

For 11X: 11.009 amu x 0.8009 = 8.817 amu

For element X: atomic mass =10.810 amu

1. The element of copper has naturally occurring isotopes with mass number of 63and 65. The relative abundance and atomic masses are 69.2% for mass = 62.93 amu, and 30.8% for mass = 64.93 amu. Calculate the average atomic mass of copper

2. Calculate the atomic mass of bromine. The 2 isotopes of bromine have atomic masses and relative abundance of 78.92 amu (50.69%) and 80.92 amu (49.31%)

Practice

Groups

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18periods

1

2

3

4

5

6

7