Orbitals Electron Configurations Orbitals

Orbitals Orbitals s orbital p orbital www.chemsheets.co.uk AS 1009 3-Jun-2015

Orbitals Orbitals Sub-level Number of orbitals in sub-level Shape (no need to learn) Maximum number of electrons in sub-level s 1 2 p 3 6 d 5 10 f 7 Even more complicated! 14 Orbitals Electrons © www.chemsheets.co.uk AS 1009 3-Jun-2015

Electron Configurations Orbitals Electron Configurations The electrons are found orbitals or electron configurations. They follow 3 rules: The Aufbau Principle The Paulie Exclusion Principle Hunds Rule Orbitals Electrons

Orbitals The Aufbau Principle- says that orbitals are “filled” from the “bottom” to the “top”, or electrons will fill the orbitals with lower energy first Nucleus First Orbital Second Orbital Orbitals Electrons

Orbitals Orbitals 1s 2s 2p 3p 3s 4s The Paulie Exclusion Principle- says that only two electrons can reside in any one orbital AND they must have opposite spin directions Hunds Rule: Every orbital has a single occupied orbital BEFORE it is doubled. AND the electrons single electrons have the same spin 1s 2s 2p 3p 3s 4s Orbitals Electrons

Arrangement of the Orbitals Aufbau Principle Some other needed knowledge Each Orbital belongs to a “Principle Energy Level” There are 4 main subtypes of orbitals in an atom s, p, d, and f. And the energy goes s>p>d>f There is 1 s orbital, 3 p orbitals, 5 d orbitals and 7 F’s There arrangement follows the periodic table Or does the periodic table follow their arrangement??? Aufbau Principle Electrons

Aufbau Principle Aufbau Principle Electrons

Electron Configurations Aufbau Principle Electron Configurations You try a orbital filling diagram of the oxygen atom. Electron Configurations of Selected Elements Element 1s 2s 2px 2py 2pz 3s Electron configuration H 1s1 He 1s2 Li 1s22s1 C 1s22s22p2 N 1s22s22p3 O 1s22s22p4 F 1s22s22p5 Ne 1s22s22p6 Na 1s22s22p63s1 Notice: each of the three 2p orbitals has one electron. The remaining electron now pairs with an electron occupying one of the 2p orbitals.

Aufbau Principle Orbitals CHEMISTRY & YOU Explain why the correct electron configuration of oxygen is 1s22s22p4 and not 1s22s22p33s1. Answer: it does not obey the Aufbau Principle Orbitals Electrons

Aufbau Principle of Phosphorous Sample Problem 5.1 The atomic number of phosphorus is 15. Write the electron configuration of a phosphorus atom. 1s 2s 2p 3p 3s 4s The electron configuration of phosphorus is 1s22s22p63s23p3. The superscripts add up to the number of electrons. Electrons

Electron Configurations Exceptional Electron Configurations. Electron Configurations This is what a usual one looks like Cr 1s22s22p63s23p63d44s2 Cu 1s22s22p63s23p63d94s2 The correct electron configurations are as follows: Cr 1s22s22p63s23p63d54s1 Cu 1s22s22p63s23p63d104s1 These arrangements give chromium a half-filled d sublevel and copper a filled d sublevel- This is because filled and half filled orbitals are more stable Orbitals Electrons

Orbitals What is the correct electron configuration of a sulfur atom? A. 1s22s22p43s23p6 B. 1s22s22p63s23p3 C. 1s22s22p63s23p4 D. 1s22s22p63s63p2 Orbitals Electrons

Orbitals What is the correct electron configuration of a sulfur atom? A. 1s22s22p43s23p6 B. 1s22s22p63s23p3 C. 1s22s22p63s23p4 D. 1s22s22p63s63p2 Orbitals Electrons

Ionization Energy Ionization Energy What is ionisation energy? Definitions Film Clip https://www.youtube.com/watch?v=ksZoOde-7zY Ionization Energy Electrons

WHAT IS IONISATION ENERGY? Ionization Energy WHAT IS IONISATION ENERGY? - Attraction between the nucleus and an electron Ionisation Energy is a measure of the amount of energy needed to remove electrons from atoms. The greater the pull of the nucleus, the harder it will be to pull an electron away from an atom. FIRST IONISATION ENERGY - Definition The energy required to remove ONE MOLE of electrons from each atom in ONE MOLE of gaseous atoms to form ONE MOLE of gaseous positive ions. e.g. Na(g) Na+(g) + e- Al(g) Al+(g) + e- Make sure you write in the (g) Ionization Energy Electrons

Successive Ionisation Energies Ionization Energy Successive Ionisation Energies What does this mean to you? Mg(g)  Mg+(g) + e- 1st I.E. =+738 kJ.mol-1 Mg+(g)  Mg2+(g) + e- 2nd I.E.= + 1451kJ.mol-1 Mg2+(g)  Mg3+(g) + e- 3rd I.E.= + 7733kJ.mol-1 Ionization Energy Electrons

Ionization Energy 1st ionisation energy. What is happening across the table? AND Down the noble gases Li 520 Na 496 K 419 Rb 408 Cs 376

Ionization Energy - Groups Ionization energies decrease going down a Group, Why? 1) Moving down a group the principle energy level increases distance of electron from the pull of the positive nucleus 2) AND here are more electrons providing inner shell shielding of the nucleus. Therefore the valence electrons are less strongly held Na 2-8-1 (IE = 496 KJ/Mol) Rb 2-8-18-8-1 (IE = 403 KJ/mol) Ionization Energy

1st ionisation energy (across period) Orbitals 1st ionisation energy (across period) Atomic Radius DECREASES, why? Increased nuclear charge (i.e. more protons) Thus a stronger attraction from nucleus to electron in outer shell Atoms get smaller Orbitals Electrons © www.chemsheets.co.uk AS 1009 3-Jun-2015

Ionization Energy Trends Orbitals General Trends Ionization energy increases as each successive electron is removed 2) Ionization energy DECREASES going DOWN a GROUP 3) Ionization energy INCREASES as you go ACROSS a PERIOD 4) The noble gases have the highest Ionization energies 5) The alkali metals have the lowest Ionization energies Orbitals

Ions Orbitals https://www.youtube.com/watch?v=vp9mfW7dqE0 IONS FORM by: ALWAYS removing the highest level of n. Or the highest energy electrons are lost when an ion is formed. AND the energy is as follows: least s<p<d<f (most) Orbitals Electrons © www.chemsheets.co.uk AS 1009 3-Jun-2015

ELECTRONIC CONFIGURATION OF IONS 3 Things: Positive ions (cations) are formed by removing electrons from atoms Negative ions (anions) are formed by adding electrons to atoms Electrons are removed first from the highest occupied orbitals SODIUM Na 1s2 2s2 2p6 3s1 1 electron removed from the 3s orbital Na+ 1s2 2s2 2p6 CHLORINE Cl 1s2 2s2 2p6 3s2 3p5 1 electron added to the 3p orbital Cl¯ 1s2 2s2 2p6 3s2 3p6 Anions are always larger than their parent atom. Cations are always smaller than their parent atom. Ions

ELECTRONIC CONFIGURATION OF IONS FIRST ROW TRANSITION METALS Despite being of lower energy and being filled first, electrons in the 4s orbital are removed before any electrons in the 3d orbitals. TITANIUM Ti 1s2 2s2 2p6 3s2 3p6 4s2 3d2 Ti+ 1s2 2s2 2p6 3s2 3p6 4s1 3d2 Ti2+ 1s2 2s2 2p6 3s2 3p6 3d2 Ti3+ 1s2 2s2 2p6 3s2 3p6 3d1 Ti4+ 1s2 2s2 2p6 3s2 3p6 Ions