Quantum Theory lesson6 sep.9 Flashcards
Quantum Theory
The theory that helps us predict the location and movement of electrons around the nucleus. Since electrons are attracted to the nucleus they are constantly orbiting around it.
Because electrons are so fast we cannot know their exact location at a given time, but we can predict their distance from the nucleus, shape of movement and the number of electrons.
Shells
The shells represent the distance from the nucleus and the energy levels. The first shell is the closest to the nucleus, and has the lowest energy level.
Valence shell
The outermost shell.
Subshell
Subshells represent the way the electrons move in the shell itself.
There are four different subshells:
S subshell- a spherical shape
P subshell- an infinity shape
D subshell- an infinity shape
F subshell- an infinity shape
Orbitals
Orbitals represent how many roads exist in each subshell.
S subshell has 1 orbital and can fit 2 electrons.
P subshell has 3 orbitals and can fit 6 electrons.
D subshell has 5 orbitals and can fit 10 electrons.
F subshell has 7 orbitals and can fit 14 electrons.
Each orbital can consist of 2 electrons at most.
The quantum values:
N represents the shell
L represents the subshell
M represents the orbital of the subshell
S represents the direction of the movement of the e–
clockwise(½) or counter clockwise(-½ ).
Aufbau rule of electron configuration definition
According to Aufbau’s law atoms will fill the shells and subshells which are the closest to the nucleus first.
Aufbau’s law
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10
Hund’s rule
“Bus Seat Rule”
Electrons will distribute themselves in orbitals of the same subshell if possible.
Paul’s rule
2 electrons cannot exist with the same quantum values.
Therefore, 2 electrons within the same orbital must move in opposite directions
(-have opposite spins ½ / -½).
Octet rule:
Every atom wants to complete its balance shell with 8 electrons- 2in the S subshell, and 6 in the P subshell, in order to reach noble gas configuration - maximal stability.
Atomic size/ Radius:
Goes up in group (↓), since there are more shells,
But Atomic size decreases in Period(→), since there are more protons that attract the valence shell.
Ionisation energy:
The amount of energy that is required to take an electron from an atom.
Decreases in group(↓) increases in Period(→).
Electron affinity:
The amount of energy that is released when an electron hits a neutral gas atom and makes it an ion.
Decreases in group(↓) increases in Period(→).
In other words, the neutral atom’s likelihood of gaining an electron.
Electro-negativity:
The ability of an atom to attract electrons when they are shared with another atom. decreases in group increases in Period.
