Atoms, Elements, Atoms, Elements, & &

The Periodic TableThe Periodic Table

MatterMatter – anything that has mass & volume – anything that has mass & volume

Element Element – a substance composed of only – a substance composed of only 1 kind of atom 1 kind of atom

AtomAtom – smallest particle of an element – smallest particle of an element

size of an atom video clipsize of an atom video clip atomic structure video clipatomic structure video clip

Atomic structure:Atomic structure:particleparticle chargecharge symbolsymbol locationlocation

NeutronNeutron NeutralNeutral nnºº in the nucleusin the nucleus

Proton Proton PositivePositive pp++ in the nucleusin the nucleus

ElectronElectron

((pp+ and + and nnº areº are

1835 x larger 1835 x larger ee--))

negative negative ee-- orbit around orbit around the nucleusthe nucleus

history of atomic modelshistory of atomic models 1803: John Dalton concluded 1803: John Dalton concluded that all matter is made of atoms.that all matter is made of atoms. 1904: J.J.Thompson discovered1904: J.J.Thompson discovered electrons & proposed theelectrons & proposed the “ “plum pudding model”plum pudding model” 1911: Earnest Rutherford 1911: Earnest Rutherford discovered the nucleus.discovered the nucleus. 1913: Neils Bohr proposed that1913: Neils Bohr proposed that electrons orbit with electrostic electrons orbit with electrostic forces rather than gravity.forces rather than gravity. the “planetary model”the “planetary model” 1926: Erwin Schrodinger 1926: Erwin Schrodinger analyzed electron orbits from a analyzed electron orbits from a geometric point using geometric point using quantum physics,quantum physics,

QuarksQuarks – small particles that – small particles that

make up protons and neutrons. make up protons and neutrons. 3 quarks held together by the 3 quarks held together by the

strong nuclear force (pstrong nuclear force (p++ or n°). or n°).

IsotopesIsotopes - Atoms of the - Atoms of the

same element with different same element with different

numbers of neutrons.numbers of neutrons.isotopes video clip

Electron energy levelsElectron energy levels 1st level = maximum 1st level = maximum 22 2nd level = maximum 2nd level = maximum 88 3rd level = maximum 3rd level = maximum 1818 4th level = maximum 4th level = maximum 3232 55thth level = maximum level = maximum 3232 66thth level = maximum level = maximum 1818 77thth level = maximum level = maximum 88

Valence Valence electrons (very outside ring) can never electrons (very outside ring) can never exceed 8 electronsexceed 8 electrons

Periodic Table of the ElementsPeriodic Table of the Elementswe will learn how to interpret the table & learn the most important element symbols.we will learn how to interpret the table & learn the most important element symbols.

The symbol: 1The symbol: 1stst letter is capital, 2 letter is capital, 2ndnd letter is lower case. letter is lower case. (most symbols are in Latin)(most symbols are in Latin)

Atomic Number = # of protons, or # of electrons. Atomic Number = # of protons, or # of electrons. (in a stable atom, the # of protons is equal to (in a stable atom, the # of protons is equal to

the number of electrons) the number of electrons)

Ex: Lithium has 3 pEx: Lithium has 3 p++ & 3 e & 3 e--

Atomic mass/weight = # of protons plusAtomic mass/weight = # of protons plus

# of neutrons. # of neutrons. (avg. is due to isotopes)(avg. is due to isotopes)

Ex: Lithium 7 has 4 neutrons. 7 – 3 = 4Ex: Lithium 7 has 4 neutrons. 7 – 3 = 4

Lithium 6 has 3 electrons. 6 – 3 = 3Lithium 6 has 3 electrons. 6 – 3 = 3

Periodic Table of the ElementsPeriodic Table of the Elements The column is called a group or family The column is called a group or family

(all elements in a family have similar characteristics)(all elements in a family have similar characteristics) The number above the column is the group number and The number above the column is the group number and

identifies the # of valence electrons.identifies the # of valence electrons. The element at the top of the column is the family name. The element at the top of the column is the family name. The row is called a The row is called a

period & tells how period & tells how

many rings of electrons many rings of electrons

the atom has.the atom has.

Mendeleev arranged the elements in the table by increasing Mendeleev arranged the elements in the table by increasing atomic number/atomic mass/number of protons.atomic number/atomic mass/number of protons.

Periodic Table of the ElementsPeriodic Table of the Elements MetalsMetals: good conductors, shiny, malleable, & ductile : good conductors, shiny, malleable, & ductile Non-metalsNon-metals: poor conductors, dull, & brittle or powdery : poor conductors, dull, & brittle or powdery Noble GasesNoble Gases – group 18 (He family), stable atoms, do – group 18 (He family), stable atoms, do

not naturally form compoundsnot naturally form compounds MetalloidsMetalloids: some characteristics of metals & some of : some characteristics of metals & some of

non-metalsnon-metals

Chemical Chemical Elements.comElements.com - An Interactive Periodic Table of the Elements - An Interactive Periodic Table of the Elements

6 most common elements found in living things:6 most common elements found in living things: 1.1. Carbon___________Carbon___________

2.2. Hydrogen_________Hydrogen_________

3.3. Oxygen___________Oxygen___________

4.4. Nitrogen__________Nitrogen__________

5.5. Phosphorous_______Phosphorous_______

6.6. SulphurSulphur

The main element in all organic compounds is The main element in all organic compounds is CarbonCarbon_ _ (more on compounds in our next unit)(more on compounds in our next unit)