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Chemistry 1 Chapter 6 Modern Periodic Table. Last Updated January 6, 2020. Antoine Lavoisier. Late 1790s French Scientists Compiled a list of elements Only 23 elements known at the time. John Newlands. 1864 English Chemist
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Chemistry 1Chapter 6Modern Periodic Table Last Updated January 6, 2020
Antoine Lavoisier • Late 1790s • French Scientists • Compiled a list of elements • Only 23 elements known at the time
John Newlands • 1864 • English Chemist • Proposed an organization scheme for the elements based on increasing atomic mass noting that properties repeated every eighth element. • Idea did not work for all elements
Meyer and Mendeleev • Meyer-German Chemist • Mendeleev-Russian Chemist • Mendeleev published his organization scheme first and is therefore given more credit.
Mendeleev Continued • Mendeleev arranged elements according to increasing atomic masses but into columns with similar properties • Was able to predict the properties of yet undiscovered elements
Not entirely accurate as new elements were discovered and atomic masses of known elements were more accurately determined.
Henry Mosley • 1913 • English Chemist • Arranged elements according to increasing atomic number • Resulted in clear Periodic Patterns
Periodic Law • The periodic repetition of chemical and physical properties of the elements when they are arranged by increasing atomic number
Review/Discuss • Groups – Columns • Periods – Rows • Main Block Elements (Groups 1A-8A or 1-2,13-18) • Transition Elements (Groups 1B-8B or 3-12) • 1-18 Newer numbering system for groups
Review/Discuss Continued • Metals • Non-metals • Metalloids • Transition • Inner Transition • Alkali-metals • Alkaline Earth Metals • Halogens • Noble Gases
Classification of the elements • Valence e- and the Periodic Table • See Figure 6-9 page 160
Blocks • s • p • d • f • Know the location of each block
Periodic Trends • Atomic Radius in picometers (1 x 10-12 meters) • Generally Decreases from left to right and increases as you move down the periodic table
Ion • Charged Particle due to loss gain or sharing of electrons • Loss of electrons = smaller radius • Gain of electrons = larger radius • Compare Trends from Fig 6-11 pg 163 to Fig 6-14 pg. 166 • Lost e- are generally valence e-
Ions Continued • Across Periods moving left to right + ions decrease in size • Ions decrease in size • Down Groups Both + and – ions increase radii
Ionization Energy- Energy required to remove an e- from a gaseous atom • First ionization energy = 1 e- to remove • Ionization Energy can be thought of as how strongly an atom’s nucleus holds on to its valence e-
Atoms with large ionization energy are less likely to form + ions • Low ionization energy indicates an atom loses e- easily likely to form + ions
Octet Rule- atoms tend to lose, gain or share e- in order to acquire a full set of eight valence e- • Electronegativity- ability of an atom to attract e- to itself in a chemical bond • Units are arbitrary and are called Paulings, for Linus Pauling
Electronegativity decrease as you move down a group and increases as you move left to right • Lowest electronegative = lower left • Highest electronegative = upper right