Chapter 6 Periodic Table World of Chemistry Harry potterHarry potter sings the element song

Periodic Table a chart that organizes information about the elements knowing an elements location in the table allows you to predict properties scientists have placed elements with similarities in the same groups on the table

History: Joseph Dobereiner – Triads (1829) made chart of groups of three elements that had similar properties ex. Ca, Ba, Sr (found Sr mass is half way between the other two)

Dobereiner’s Triads Triad 1Triad 2Triad 3 First element Calcium 40.1Chlorine 35.3Sulfur 32.1 Third element Barium 137.3Iodine 126.9Tellurium Average Second Element Strontium 87.6Bromine 79.9Selenium 79.0

John Newlands – Law of Octaves (1863) arranged in order of atomic mass appeared to be a repetition of properties every eighth element arranged elements into groups of 7 Law of Octaves – same properties repeat every 8 th element (but it didn’t account for Noble gases and transition metals)

Law of Octaves LiBeBCNOF NaMgAlSiPSCl K

Song-elemental Funkiness Mendeleev’s Periodic Table Dmitri Mendeleev and Lothar Meyer both demonstrated a connection between atomic mass and properties -Mendeleev published his table first and better demonstrated its usefulness Video

-placed elements with similar properties in vertical columns called groups or families -horizontal rows are periods -if no known element fits in a particular place, he left a blank (predicted the properties of it for someone to discover later)

Mendeleev’s Prediction Ekasilicon (Es) (predicted properties) Atomic Mass: 72 High Melting Point Density: 5.5 g/ml Dark gray metal Will obtain from K 2 EsF 6 Slightly dissolved by HCl Will form EsO 2 Density of EsO 2 : 4.7 g/ml Germanium (Ge) (1886) (actual properties) Atomic Mass: Melting Point: 945° C Density: g/ml gray metal Will obtain from K 2 GeF 6 Not dissolved by HCl Will form GeO 2 Density of GeO 2 :4.7 g/ml

Mendeleev’s Periodic Law physical and chemical properties of elements were periodic functions of their atomic mass by arranging by atomic mass he did find he had some elements in groups with different properties (ex. Te and I, Co and Ni)

Modern Periodic Table -Henri Moseley’s discovery of the atomic number corrected Mendeleev’s problems and led to the modern table

Modern Periodic Law properties of elements are periodic functions of their Atomic numbers found atoms of similar electron configurations found in similar groups The Development of the Periodic Table

Chinese Periodic Table

German Table (Periodensystem der Elemente )

Russian

Tableau de classification périodique des éléments Métaux alcalins Métaux alcalino- terreux Hydrogène Métaux de transition Semimétaux Métalloïdes Non-métaux LanthanidesGazes rares ActinidesNon-catégorisé Z N A Numéro atomique Nombre de neutrons Masse atomique E Élément Nom Symbole

Norwegian et_i_stor_utgavehttp://no.wikipedia.org/wiki/Periodesystem et_i_stor_utgave Romanian

Parts of the Periodic Table Groups or Families - vertical column of elements w/ similar properties Elemental Funkiness

Group 1- Alkali Metals Group 2 – Alkaline Earth Metals Group 16- Chalcogens Group 17 – Halogens Group 18 – Noble or Inert gases 3-12 – Transition metals Staircase- metalloids Bottom rows- Rare earth metals (Lanthanoids & Actinoids or Lathanides & Actinides)

Periods - horizontal rows (of elements w/ common outer energy level)

Properties of Elements Metals: -left side of staircase -hard, shiny, conduct heat or electricity well, malleable, ductile -have 3 or fewer electrons in outer level (3 or less dots in dot diagram)

Nonmetals -right side of staircase -gases or brittle solids, dull surfaces, used as insulators -have 5 or more electrons in outer energy level

Metalloids -have properties of both metals and non metals -found on staircase Reading the Periodic Table

Organizing elements by electron configuration Atoms in same group have similar chemical properties because they have similar electron configurations and similar # of valence electrons Period numbers  tell us the outer most energy levels The periodic table not only has rows & columns but sections or blocks representing the sublevels

s - block d - block p - block f -block Outer energy levels

The energy level number in front of (s) is always the period number The energy level number in front of the (p) is the period number The energy level number in front of the (d) is one less than the period number The energy level number in front of the (f) is 2 less than the period number

Periodic Trends Properties of elements change in predictable ways depending on their location on the periodic table because of their electron configuration

Atomic Radius -half the distance between adjacent nuclei in two atoms of the element bonded together

Trends:

Ionic Radius when elements lose or gain electrons to form ions their size increase and decreases an atom that loses electrons and becomes positively charged gets smaller an atom that gains electrons and becomes negatively charged gets larger

Trends: Generally decreases Positive ions decreaseNegative ions decrease

Ionization Energy -energy required to remove an electron from a gaseous atom

Trends:

Electronegativity the relative ability of the atoms to attract electrons in a chemical bond

Electronegativity Trends:

Chemical Reactivity Tendency of a substance to undergo a chemical change Metals- reactivity increase moving towards bottom left (Cesium) Nonmetals- reactivity increase moving towards top right (fluorine)

Quest 16 multiple choice 3 going from element to configuration 7 going from configuration to name Short answer- id elements as metal/non/metalloid, and the group name Know: History (Triads, octaves, Mendeleev), Modern periodic law=atomic mass, trends, families)