The Periodic Table GPS 7

History of the Periodic Table Mendeleev –credited for creating the first periodic table –arranged elements in order of increasing atomic mass Video

History of the Periodic Table Moseley –arranged elements in order of increasing atomic number –results in interesting periodic trends

Moseley proposed the modern periodic law. Modern periodic law: –the chemical properties of elements are periodic functions of their atomic numbers History of the Periodic Table

Groups and Periods Group or Family –elements within the same column on the periodic table Period –elements within the same row on the periodic table

Groups on the Periodic Table

Periods on the Periodic Table Lanthanides Actinides

Metals, Nonmetals, Metalloids

Metalloids Metalloids are commonly used in semiconductors Semiconductors are used in solar cells, computer chips, and LEDs (among other applications)

Practice: Which of the elements below are metals? calcium bromine hydrogen iodine lead silver lithium magnesium copper argon aluminum zinc silicon boron neon oxygen potassium helium

Practice: Which elements are alkali metals? calcium bromine hydrogen iodine lead silver lithium magnesium copper argon aluminum zinc silicon boron neon oxygen potassium helium

Practice: Which elements are alkali earth metals? calcium bromine hydrogen iodine lead silver lithium magnesium copper argon aluminum zinc silicon boron neon oxygen potassium helium

Physical Properties of Metals and Nonmetals MetalsNonmetals Aluminum Gold Copper wire Sulfur powder Hydrogen gas bubbling through a solution Liquid Bromine

Physical Properties of Metals and Nonmetals PropertyMetalsNonmetals DensityHigher densitiesLower densities ConductivityVery highVery low Melting pointHigher temps.Lower temps. Boiling pointHigher temps.Lower temps. MalleabilityVery goodVery poor DuctilityVery goodVery poor

Chemical Properties of Groups Octet Rule –an atom that has a full outer-most energy level is unreactive (usually it is full with 8 electrons, but there are some exceptions) most atoms want to satisfy the octet rule atoms react with each other in order to form the most stable electron configuration, which is an octet (for most)

Octet Rule Exceptions (for the curious) 2 electrons: hydrogen and helium 4 electrons: berrylium 6 electrons: boron family 7 electrons: nitrogen (sometimes) More than 8 electrons: phosphorus and sulfur (you will not be tested on octet exceptions)

Octet Rule: Forming Bonds Atoms will gain, lose, or share electrons in order to fulfill the octet rule When electrons are transferred, ions are formed. Ions are attracted to each other and form ionic bonds When electrons are shared, covalent bonds are formed

Chemical Properties of Groups Oxidation Numbers

Chemical Properties of Groups Example: For the following elements, show the ion that it most commonly forms (using proper notation): Chlorine Sodium Nitrogen Sulfur Neon Boron Magnesium Lead

What do Groups/Families have in common? Elements in the same group on the periodic table have similar chemical properties since they have the same number of _________ __________. valence electrons

Oxidation Numbers and Ions Ions –atoms with charges (i.e. not neutral) Oxidation numbers –indicate the ion that an atom most always forms during chemical reactions Anion –a negatively charged ionEx: O 2- Cation –a positively charged ionEx: Na 1+

Cation or Anion? Is the atom on the left a cation or anion?

Periodic Trends: Ionic Radius Ionic Radius CationsAnions

Periodic Trends: Ionic Radius Ionic Radius the ionic radii of cations are smaller than their atomic radii because electrons were lost the ionic radii of anions are larger than their atomic radii because electrons were gained

Periodic Trends: Atomic Radius Atomic Radius –½ the distance between the nuclei of two atoms of the same element when the atoms are bonded Two identical atoms

Periodic Trends: Atomic Radius Atomic Radius

Periodic Trends: Atomic Radius Atomic Radius Trend: Explanation –Trend across the periods: As you move left to right across the periodic table, the number of protons _________ therefore the electrons are being pulled _______ strongly toward the nucleus, thus making the atomic radius _________. –Trend down groups: As you move down a group on the periodic table, the number of energy levels ________ therefore the atomic radius ___________

Periodic Trends: Ionization Energy Li → Li + + e - Ionization Energy –the energy required to remove an electron from an atom (thus, creating a cation) –also known as First Ionization Energy when only removing one electron from the outer energy level Example:

Periodic Trends: Ionization Energy Metal/ Nonmetal Type of Ion formed Gain/Lose electrons for an octet? First Ionization Energy (high or low) Metal Nonmetal Cations Anions Lose Gain Low High Trend across the periods:

Periodic Trends: Ionization Energy Trend down a Group: Shielding effect –inner electrons block the attraction of the nucleus for outer electrons, thus _______ first ionization energy –The _______ the shielding effect, the _____ the ionization energy (the opposite is also true). Ionization energy ______ as you go down a group

Periodic Trends: Ionization Energy Ionization Energy

Periodic Trends: Electronegativity Electronegativity –the tendency of an atom to attract electrons to itself when it is bonded to another atom –Imagine a “tug-of-war” over valence electrons involved in making the bond Example: A and B have the same electronegativity and are sharing valence electrons equally B is slightly more electronegative than A, so the electrons are more highly attracted to B B is much more electronegative than A, so the electrons are so highly attracted to B that they leave A and transfer to B

Periodic Trends: Electronegativity Electronegativity –the tendency of an atom to attract electrons to itself when it is bonded to another atom

Periodic Trends: Electronegativity Trend across the periods: –Recall: nonmetals tend to form _______ (negative ions), thus they are more prone to want to _______ electrons. Therefore they will pull electrons ______ strongly when bonded to another atom and have _______ electronegativity Trend down a group: –The ______ the atoms that are bonded, the ________ from the nucleus the valence electrons become. The farther away the electrons become, the _______ attracted they are to the nucleus, thus ________ electronegativity.

Periodic Trends Example: Put the following elements in order of: a. increasing ionization energy b. increasing electronegativity c. increasing atomic radius zinc, rubidium, fluorine, calcium, silver, oxygen, potassium, sulfur

Periodic Trends: Reactivity of Nonmetals Reactivity –The tendency to change into something else when mixed with another substance

Periodic Trends: Reactivity of Metals

Periodic Trends: Reactivity Which two groups are the most reactive? Why? Which is the most reactive nonmetal? Why? Which is the most reactive metal? Why?

Periodic Trends: Diatomic Molecules Naturally occurring diatomic molecules: Br 2, I 2, N 2, Cl 2, H 2, O 2, F 2 - these occur as gases at room temperature * except Br 2 (liquid at room temp) * except I 2 (solid at room temp) - naming: ex: O 2 oxygen gas N 2 nitrogen gas Br 2 liquid bromine I 2 solid iodine

Practice: Which of the following elements has the greatest electronegativity? Least? fluorinecalciumsiliconbarium

Practice: Which of the following elements has the greatest ionization energy? Least? fluorinecalciumsiliconbarium

Practice: Which of the following elements has the greatest shielding effect? lithiumcalciummagnesiumbarium

Practice: According to the modern periodic law, the chemical properties of elements are periodic functions of their _____.

Resources u/classes/phys314/lectures/period/period.htmlhttp://images.google.com/url?q= u/classes/phys314/lectures/period/period.html -chem.htmhttp:// -chem.htm dex4.htmlhttp://serc.carleton.edu/usingdata/nasaimages/in dex4.html ystalmaker/resources/VFI_Atomic_Radii.jpghttp:// ystalmaker/resources/VFI_Atomic_Radii.jpg hapter7/CommonCations.htmlhttp://intro.chem.okstate.edu/1314F00/Lecture/C hapter7/CommonCations.html

SOL covered during lesson CH 2 d, e, f, g, h