The Elements (Chapter 7) Flashcard

Johann Dobereiner
German Chemist. In 1817 discovered Law of Triads
Law of Triads
Groups of 3 Related Elements have similar properties
John Newlands
English Chemist. In 1863 discovered the Law of Octaves
Law of Octaves
The same properties appear every 8th element when elements are listed in order of their atomic masses.
Dmitri Mendeleev
Russian Chemist. During 1860’s developed the 1st periodic table. Suggested periods of varying lengths based on atomic masses. Predicted Properties of yet undiscovered elements (Gallium, Germanium, Scandium)
Mendeleev’s Periodic Law
Properties of elements are periodic functions of their atomic masses.
Modern Periodic Law
Properties of elements are functions of their atomic numbers. (Developed by Henry Moseley)
Henry Moseley
British Scientist. In 1913 he developed the Modern Periodic Law.
Atomic Number
The number of protons in an atom. In a neutral atom this refers to the number of electrons.
Vertical Columns of elements. AKA Family
Horizontal Rows of elements. AKA series
Element Collections
Alkali Metal, Alkaline Earth Metals, Lanthanoids, Actinoids, Transition Metals, Chalcogens, Halogens, Noble Gases
Octet Rule
An atom with 8 electrons in its outer shell is particularly stable. (an atom will try to have 8 electrons in its outer shell)
S – Helium and First 2 Columns in Periodic Table
P – Last 6 Columns (minus Helium)
D – Transition Metals (middle area) (n-1 for easy electron configuration)
F – Lower 2 rows. (n-2 for easy electron configuration)
Shiny, Malleable, Ductile, Conduct heat & electricity, Have few electrons in outer shell, lose electrons in chemical reactions
Non Metals
Dull, Brittle, Non-Ductile, Insulator of heat & electricity, Have many electrons in outer shell, gain electrons during chemical reactions
Elements adjacent to bold diagonal line.
Factors in Ionization Energy
Greater Nuclear Charge (direct relationship)
Greater Principle Quantum # (Inverse Relationship)
Greater Shielding effect (Inverse Relationship)
Half/Completely filled sublevels (No Relationship)
High Ionization Energy
Towards upper right corner, half filled or full shells
High Atomic Radius
Towards bottom left corner, more electrons than protons
Large Ions
Closer to upper right corner, more electrons gained in reaction
Increases from left -> Right. Increases from top -> Bottom. Noble gases have no electronegativity. Fluorine has highest electronegativity. Francium has the lowest.
Boiling point trend
Higher in middle of table. Lower on the ends
Density Trends
Higher in the middle of the table. Lower on the edges.

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