ELECTRON CONFIGURATIONS. Electron Configuration:. A method for communicating the location and number of electrons in the electron energy levels. 3p 5 Principal Quantum Number = 3 Orbital = p Number of electron(s) in the orbital(s) = 5.
A method for communicating the location and number of electrons in the electron energy levels.
Principal Quantum Number = 3
Orbital = p
Number of electron(s) in the orbital(s) = 5
(means building-up in German) in the ground state, the electrons will fill the atomic orbital of lowest energy.
Chromium (24 electrons)
EC = 1s2 2s2 2p6 3s23p64s23d4 is INCORRECT
EC = 1s2 2s2 2p6 3s23p64s13d5 is CORRECT!
The d-orbital becomes half-filled so, it changes to 4s13d5 instead.
The next element, Manganese will have an EC of:
1s2 2s2 2p6 3s23p64s23d5
EC = 1s2 2s2 2p6 3s23p64s23d9 is INCORRECT
EC = 1s2 2s2 2p6 3s23p64s13d10is CORRECT
Additional exceptions are Mo 5s14d5; Ag 5s14d10; Au 6s15d10 That is reasonable considering their position on the periodic chart.
Na: 1s2 2s2 2p6 3s1Expanded form
Na: [Ne] 3s1Condensed form
The “ [Ne] ” is called a kernel = [closest noble gas]
ONLY NOBLE GASES CAN BE USED AS THE KERNEL
ORBITAL-BOX DIAGRAMS filling:
Similar to EC, except, you are now expected to draw out the orbitals and place the electrons to show proper spinning.
Rules for drawing orbital-Box diagrams
each orbital can hold 2e-, where those 2e- are always in oppositespin.
2) Hund's Rule –
Electrons occupy all the orbitals of a given sublevel singly before pairing begins. Spins of electrons in different incomplete orbitals are parallel in the ground state.The most stable arrangement of electrons in the subshells is the one with the greatest number of parallel spins.
Suppose we want to draw the orbital-box diagram of filling:carbon:
Step 1: Draw the orbitals.
Step 2: Fill the electrons in the 1st two s-orbitals, showing opposite spin. These electrons must fill the lower energy orbitals first before advancing to the next higher energy level (AUFBAU’s PRINCIPLE).
Step 3: Fill the 2p sublevels one at a time (HUND’s RULE).
The electrons in the outermost shell of the Bohr diagram.
Lose electrons = become positively charged (Cation)
Gain electrons = becomes negatively charged (Anion)
ELECTRON CONFIGURATIONS OF IONS filling:
Electrons do notcome out the same way as we put them in according to the Aufbau Principle.
Electrons leave the outer most shell first.
Let's look at V vs V2+