Chem Exam 2

periodic table trends, electron orbital filling rules

Heisenberg Uncertainty Principle

It is fundamentally impossible to determine both velocity (wave nature) and position (particle nature) at the same time.

Schrodigner Equation

Gives atomic orbitals (probability of finding electrons in a region of space)

Shielding

each electron experiences attraction to the nucleus and is repelled from other atoms

Aufbau principle

electrons occupy the lowest energy orbitals first

Pauli Exclusion principle

no 2 electrons in an atomic orbital may have the same spin

Hund’s Rule

when filling orbitals with the same energy, electrons fill them singly with parallel spin and then start to pair.

Main group elements

elements that end in the s or p block

Transitional elements

elements that end in the d block

Electron configuration exception

half filled or fully filed d orbitals are more stable (ex. chromium and copper)

Noble Gasses

Have 8 electrons (group 8A) except He

Akali Metals

Most reactive and has 1 more electron than noble gasses

Alkaline earth

2A 2nd most react and 2 more electron than noble gasses

Chalcogens

6A moderately reactive non metals

Halogens

most reactive non metals 7A

Atomic size periodic trends

decreases across and increases down

isoelectronic

atoms and ions that have the same number of electrons

Metallic character periodic trend

decreases across and increases down

Electronegativity periodic trend

increases across and decreases down

Incomplete octects

molecules or ions with >8 electrons (ex B, Be, and Al)