MIDTERM STUDY (unit 4/5 Flashcards
Only s and p orbitals are
Valence electrons
Valence electrons:
e- in outer most energy level
s sublevel:
2 e- and Sphere shape
p sublevel:
6 e- and dumbbell shape
Principles that govern electron configuration:
- Pauli Exclusion Principle
- Hund’s Rule
- Aufbau Principle
Pauli Exclusion Principle:
2 e- in same orbital must have opp spins
Hunds Rule:
e- in same sublevels occupy empty orbitals before they pair up
Aufbau principle:
e- occupy positions of lowest energy level first
Orbital Notation:
shows all e- in energy level order, with e- pairing, and opp spins
Lewis Dot Notation:
shows only valence e-
Bohr Model Diagram:
shows all e- per energy level (does not delineate between sublevels)
Electron Configuration:
use of superscripts to show the # of electrons per sublevel
Nobel Gas Configuration:
use of Nobal Gas from the period above, then show configuration of e- after that noble gas
Isoelectronic:
atoms of two different elements with the same # of e-
Dimitri Mendeleev:
developed periodic table of known elements and arranged them in order of increasing atomic mass and later ordered according to chemical properties
What did Mendeleev predict about the empty spaces in his periodic table:
they were undiscovered elements
What was the problem with Mendeleev’s new periodic table:
When elements were arranged according to similar properties, some had to be placed out of order of atomic mass
Henry Moseley:
ordered elements by atomic number (# of p+)
Periodic Law:
states that the physical and chemical properties of elements are periodic functions of their atomic #’s