History/Trends Of The Periodic Table Flashcards
Who made periodic law and what does it say
Dmitri Mendeleev; properties of elements are a function of their atomic mass
What did Mendeleev predict?
The existence of elements that weren’t discovered yet
What did William Ramsay do and when?
Late 1800’s, discovered the noble gases Ne, Ar, Kr, Xe, and Radon (Ra)
What did Henry Moseley do
1913, used X-Rays to determine each element had a certain amount of protons, called the proton count the atomic number, rearranged periodic table by atomic number
How did Henry Mosely rewrite the Periodic Law
he changed it to “ Properties of elements are a periodic function of their atomic number.”
Properties of metals
Malleable, Ductile, Lustrous, Good Conductor, High Melting/Boiling point, loses electrons when bonding with another element
Johann Dobereiner
Investigated calcium, barium, and strontium; found they had similar atomic masses
Dobereiner’s theory?
Triad Theory - elements grouped in threes based on similar properties and relationships between atomic masses
What did John Newlands do?
Created system where elements are placed in order of increasing atomic mass.
What theory/law did John Newlands have?
Law of Octaves - there’s a repetition of properties every eighth element
How did Dmitri Mendeleev rearrange the periodic table?
Arranged them with increasing atomic mass, but made the rows and groups varied in length so that elements with similar characteristics could be grouped
What’s ionization energy
Energy needed to remove 1 electron from an atom in the gaseous phase
Equation for electrons per energy level
e-= 2 x n^2
n = energy level
What’s electronegativity
The ability of an atom to pull on an electron
Why does ionization energy increase going up and right
smaller energy levels, stronger nuclear charge
