Chemistry Peoples and Laws

Hund’s Rule
Single electrons with the same spin must occupy each energy-equal orbital before additional electrons with opposite spins can occupy same orbitals.
Pauli Exclusion Principle
A max of 2 electrons can occupy a single atomic orbital, but only if they have opposite spins.
AufBau Principle
Each electron occupies the lowest energy orbital available.
Principle Quantum Number
Indicates relative sizes and energies of atomic orbitals.
Quantum Mechanical Model of the Atom
Shows electrons treated as waves; doesn’t show movement or path.
Heisenberg Uncertainty Principle
It is fundamentally impossible to precisely know both the velocity and position of a particle at the same time.
Planck’s Constant
6.626 x 10(-34) J/s
Octet Rule
Atoms tend to lose, gain, or share, electrons in order to acquire a full set of eight valence eletrons
Ions
Have charge due to loss/gain of electrons. Valence Electrons are lost first.
Group 15 Electron dot structure
.
.N..
.
Group 4 Electron dot structure
.
.C.
.
John Newlands
(1864) Proposed an organizational structure because he recognized a pattern: properties repeated every 8 elements (Law of Octaves).
Who published the periodic table and in what year?
In 1869 German Meyer and Russian Mendeleev published the periodic table, which organized elements by increasing atomic # and mass.
Who complied a list of elements in the 1700’s?
Lavoissier, also created the Law of Conservation of Matter!
Periodic Law
There is periodic repetition of chemical and physical properties of the elements when they are arranged by increasing atomic #.
Meyer, what he do?
Demonstrated a connection between atomic mass and elemental properties and published the periodic table with Mendeleev in 1869.
Mendeleev, what he do?
Demonstrated a connection between atomic mass and elemental properties and published the periodic table with Meyer in 1869. Also predicted the existence and properties of undiscovered elements.
Henry Moseley, what he do?
Discovered that atoms contain a unique number of protons called the atomic #. Arranged elements in order of increasing atomic number, which resulted in a periodic pattern of properties.
Representative Elements
Elements from groups 1 and 2 and 13 through 18.
Transition Metals
Groups 3-12
Inner Transition Metals
(F-Block) Group 8
Speed of Light
3 x 10(8)
Which color has most frequency and the shortest wavelength?
violet
Most reactive element AND largest atomic radius?
Francium
Electronegativity definition and trend
Def= Atom’s ability to attract electrons in a chemical bond. Fluorine has greatest electronegativity.
Atomic Radius trend
Francium has greatest atomic radius
Ionization Energy trend
Fluorine has greatest
Metalloids
Elements near squigly line
Erwin Schrodinger
“Electrons are waves”