Atomic Structure Atomic Structure &&

Mixtures, Compounds, Mixtures, Compounds, Elements Elements

Size of the AtomSize of the Atom

►Average sized atom 0.00000003 cmAverage sized atom 0.00000003 cm►Aluminum foil 50,000 atoms thickAluminum foil 50,000 atoms thick►1 penny 1 penny

20,000,000,000,000,000,000,000 20,000,000,000,000,000,000,000 atoms of copper and zinc (20 thousand atoms of copper and zinc (20 thousand billion billionbillion billion

Parts of the AtomParts of the Atom

►Proton- Positive (+) particle (nucleus)Proton- Positive (+) particle (nucleus)►Determines the elementDetermines the element

►Neutron- Neutral (0)particle (nucleus)Neutron- Neutral (0)particle (nucleus)►Nucleus- Central, dense core of atomNucleus- Central, dense core of atom

Protons and neutrons are found in the Protons and neutrons are found in the nucleus of the atom and make up almost nucleus of the atom and make up almost all the mass of the atom. all the mass of the atom.

►Electron- Negative (-) particle (electron Electron- Negative (-) particle (electron cloud around nucleus)cloud around nucleus)

Modern view of the atomModern view of the atom

► The atom is mostly empty spaceThe atom is mostly empty space►Nucleus – Protons and neutronsNucleus – Protons and neutrons► Electron cloud is the area where electrons Electron cloud is the area where electrons

of an atom are most likely found. of an atom are most likely found.

Counting the Pieces ReviewCounting the Pieces Review

►Atomic Number= Number of protonsAtomic Number= Number of protons►Atomic Mass= Protons + NeutronsAtomic Mass= Protons + Neutrons►# of protons determines kind of atom. # of protons determines kind of atom. ►Neutral Atom= the same number of Neutral Atom= the same number of

protons and electrons protons and electrons ►All particles in the atom have mass. All particles in the atom have mass. ►Proton= 1amu (atomic mass unit)Proton= 1amu (atomic mass unit)►Neutron= 1amuNeutron= 1amu►Electrons have a very small mass Electrons have a very small mass

Atoms and ElementsAtoms and Elements►Atoms of different elements are differentAtoms of different elements are different

Determined by # of protonsDetermined by # of protons

►Atoms of the same element are almost the Atoms of the same element are almost the samesame Isotopes have a different number of neutronsIsotopes have a different number of neutrons Does not change the charge of the atom.Does not change the charge of the atom. Occur naturally and share the same propertiesOccur naturally and share the same properties Some are unstable and the nucleus can Some are unstable and the nucleus can

change composition (radioactive isotopes)change composition (radioactive isotopes)

IsotopeIsotope

Naming the IsotopesNaming the Isotopes

►3322He He

►4422HeHe

► 121266CC

► 141466CC

► 2352359292UU

► 2392399292U U

Mass number of this atom

Atomic numberof the element

This atom of hydrogen has two protons and one

neutron. 1 + 1+ 1= 3 amu

Atomic MassAtomic Number

Element Symbol

Write the isotopes of Hydrogen shown.

11H

21H

31H

Atomic MassAtomic Mass

►The atomic mass is not a whole The atomic mass is not a whole number because it is a weighted number because it is a weighted average of all the oxygen isotopes in average of all the oxygen isotopes in the world. the world.

Measuring Atomic MassMeasuring Atomic Mass

►Atomic mass is measured in Atomic Atomic mass is measured in Atomic Mass Units or AMU’s and is the Mass Units or AMU’s and is the addition of the number of Protons and addition of the number of Protons and Neutrons in an atom. Neutrons in an atom. Same number of electrons &

Protons Neutrons different.

Atomic Mass=________

Atomic Mass=________

ElementElement►An element is a pure substance that An element is a pure substance that

cannot be broken down into simpler cannot be broken down into simpler substances and have the same propertiessubstances and have the same properties

► Classified by propertiesClassified by properties►Grouped into categories using these Grouped into categories using these

propertiesproperties►MetalsMetals►MetalloidsMetalloids►Non-metalsNon-metals

ReviewReviewFill in this chart….Fill in this chart….

► The protons and neutrons are found in The protons and neutrons are found in the…………….. of the atom, called the nucleus.the…………….. of the atom, called the nucleus.

► The ................. zoom around the nucleus in The ................. zoom around the nucleus in shells. The 1st shell, which is .................. the shells. The 1st shell, which is .................. the nucleus, can hold.... electrons, whereas the nucleus, can hold.... electrons, whereas the 2nd and 3rd shells can hold ...... electrons.2nd and 3rd shells can hold ...... electrons.

ReviewReviewGive the Give the numbers of numbers of protons, protons, electrons & electrons & neutronsneutrons

a) a) 14 14 7 7 N N

b) b) 20 20 10 10 Ne Ne

c) c) 19 19 99 F F

d)d)39 39 1919 K K

e) e) 60 60 2727 Co Co

f)f)235 235 9292 U U

ProtonsProtons NeutronNeutronss

ElectroElectronsns

A)A)

B)B)

C)C)

D)D)

E)E)

F)F)

7 7 7

10 10 10

9 10 9

19 20 19

27 33 27

92 143 92