ATOMIC STRUCTURE electron configuration of atoms and ions of the

1. ATOMIC STRUCTURE • electron configuration of atoms and ions of the first 36 elements (using s,p,d notation) • periodic trends in atomic radius, ionisation energy and electronegativity • comparison of atomic and ionic radii

2. Electron arrangements in the atom

3. Boundary Surfaces of the 4f Orbitals

4. Energy levels, sub-levels and orbitals Energy levels • Electrons occupy distinct energy levels (or shells) arranged around the nucleus. Energy sub levels • The different main energy levels have different sub-levels in them There are four types: s, p, d, f • The number of sublevels is determined by the energy shell. One in Level 1, 2 in Level 2 etc

5. Orbitals • Electrons occupy orbitals in pairs, with each member of the pair having opposite spin, which cancel. Number of orbitals • s sublevel has 1 orbital • p sublevel has 3 orbitals • d sublevel has 5 orbitals • f sublevel has 7 orbitals

6. A Cross Section of the Electron Probability Distribution for a 3p Orbital

7. Energy Orbital arrangements in Atoms 3d 3d 3d 3d 3d Level 3 has 3 sublevels (s,p and d) with one orbital in the first (3s), 3 orbitals in the second (3p) And 5 orbitals in the third (3d) 3p 3p 3p 3s Level 2 has 2 sublevels (s and p) with one orbital in the first (2s) and 3 orbitals in the second (2p) 2p 2p 2p 2s Level 1 has just 1 sublevel consisting of one orbital (1s) 1s

8. Energy level Electron Arrangements in Orbitals 3d n=4 4s 3p What atom is this? n=3 3s 2p Ne n=2 2s n=1 1s Electrons fill orbit of lowest energy first. Write the order of subshell filling using the graph 1s 2s 2p 3s 3p 4s 3d

9. In the normal ground state of an atom, the electrons occupy orbitals with the lowest possible energies. On heating, the electrons can be excited to orbitals with higher energy - the ‘excited state’. • As the electrons fall back to lower energy levels (orbitals) they will emit electromagnetic radiation, which is often in the region of visible light ie. it appears coloured. • Each element has its own characteristic emission spectrum that can be used to identify that element, its “chemical fingerprint”.

10. Atomic orbitals define regions of space in which there is a high probability of finding an electron. Each orbital has a particular shape and associated energy values.

11. Rules For Filling Orbits • Each orbit can hold 2 electrons only an orbital containing two electrons is a filled orbit • Electrons filling the same orbit must have opposite spins indicated by arrows • Electrons fill the lowest energy sublevels first • The lowest or most stable arrangement of electrons in a sublevel is the one with the greatest number of parallel spins (Hunds Rule) • This means when orbitals of the same energy are available, electrons will avoid pairing if possible, by entering separate orbits

12. Energy level The Electron Arrangement for Ne is 3d n=4 4s 3p n=3 3s 2p n=2 2s n=1 1s the electron configuration for Ne using the correct format is : 1s2 2s2 2p6

13. Write the electron configuration then name the atom Energy level 3d n=4 4s 3p n=3 3s 2p n=2 2s n=1 1s

14. Electronic Configuration - ways to write them O: or Cl: or K: or 1s2 2s2 2p4 [He]2s2 2p4 1s2 2s2 2p6 3s2 3p5 [Ne] 3s2 3p5 1s2 2s2 2p6 3s2 3p6 4s1 [Ar]4s1 The electrons in the outermost shell of an atom are called its valence electrons O: [He]2s2 2p4 Core electrons Valence electrons

15. Energy level 3d n=4 4s 3p n=3 3s 2p n=2 2s n=1 1s Write the Electron Arrangement for Ti [Ar] 4s2 3d2

16. Energy levels and sub-levels

17. Energy levels and sub-levels

18. Energy levels and sub-levels

19. Energy levels and sub-levels

20. Energy levels and sub-levels

21. Energy levels and sub-levels

22. Energy levels and sub-levels

23. Energy levels and sub-levels

24. Energy levels and sub-levels

25. Energy levels and sub-levels

26. Energy levels and sub-levels

27. Energy levels and sub-levels

28. Energy levels and sub-levels

29. Energy levels and sub-levels

30. Energy levels and sub-levels

31. Energy levels and sub-levels

32. Energy levels and sub-levels

33. Energy levels and sub-levels

34. Energy levels and sub-levels

35. Energy levels and sub-levels

36. Energy levels and sub-levels

37. Energy levels and sub-levels

38. Energy levels and sub-levels

39. Energy levels and sub-levels

40. Atomic Orbitals

41. The order in which the orbitals fill in atoms

42. Hydrogen 1s, 2s, and 3s Orbitals

43. Three 2p Orbitals

44. Boundary Surfaces of the 3d Orbitals

45. Energy level Copper has a unique electron configuration 3d n=4 4s 3p n=3 3s 2p n=2 2s n=1 1s Write the Electron Arrangement for Cu Extra stability is gained when the 3d orbitals are half filled or completely filled [Ar] 3d10 4s1

46. Energy level Chromium has a unique electron configuration 3d n=4 4s 3p n=3 3s 2p n=2 2s n=1 1s Write the Electron Arrangement for Cr Extra stability is gained when the 3d orbitals are half filled or completely filled [Ar] 3d5 4s1

47. Orbitals Being Filled vs. Position in Periodic Table

48. Atomic and Ionic Radii It is impossible to measure the atomic radius of an atom but we can measure the distances between adjacent nuclei in substances In metals we look at half the distance between adjacent nuclei In non metals we look at covalent bonds - that is half the distance between nuclei of like atoms covalently bonded together Half this distance between nuclei

49. Ionic radii Radii increase down group Radii decrease across period

50. 2006 Bonding Exam Write the electron configuration for: Cr Mn Mn2+ Cr 1s22s22p63s23p64s13d5 OR [Ar] 4s13d5 OR [Ar]3d54s1 Mn 1s22s22p63s23p64s23d5 OR [Ar] 4s23d5 OR [Ar]3d54s2 Mn2+ 1s22s22p63s23p63d5 OR [Ar] 3d5 Two correct..