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Subshells & orbitals

Subshells & orbitals. The ionisation energy graph does not increase steadily across a period. The ionisation energy graph does not increase steadily across a period The small decreases are due to sub-shells or sub-energy levels.

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Subshells & orbitals

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  1. Subshells & orbitals

  2. The ionisation energy graph does not increase steadily across a period

  3. The ionisation energy graph does not increase steadily across a period • The small decreases are due to sub-shells or sub-energy levels

  4. The ionisation energy graph does not increase steadily across a period • The small decreases are due to sub-shells or sub-energy levels • This means there are different energy levels within one energy level

  5. The ionisation energy graph does not increase steadily across a period • The small decreases are due to sub-shells or sub-energy levels • This means there are different energy levels within one energy level • All electrons in the same subshell have the same energy

  6. The ionisation energy graph does not increase steadily across a period • The small decreases are due to sub-shells or sub-energy levels • This means there are different energy levels within one energy level • All electrons in the same subshell have the same energy • The sub-shells are labelled s, p, d and f

  7. The ionisation energy graph does not increase steadily across a period • The small decreases are due to sub-shells or sub-energy levels • This means there are different energy levels within one energy level • All electrons in the same subshell have the same energy • The sub-shells are labelled s, p, d and f • Sub-shell energy levels: s < p < d < f

  8. Each shell or energy level has one more sub-shell than the previous one

  9. Each shell or energy level has one more sub-shell than the previous one • 1st shell 1s • 2nd shell 2s 2p • 3rd shell 3s 3p 3d • 4th shell 4s 4p 4d 4f

  10. Each sub-shell has a maximum number of electrons it can hold.

  11. Each sub-shell has a maximum number of electrons it can hold.

  12. Each sub-shell has a maximum number of electrons it can hold. • Hence the 2nd energy level with an s sub-shell (2 electrons) and a p sub-shell (6 electrons) can hold a total of 8 electrons.

  13. Electron Arrangement & Electronic Configuration • The arrangement of electrons when written in shells or energy levels such as 2 , 9 , 1 is called the electron arrangement

  14. Electron Arrangement & Electronic Configuration • The arrangement of electrons when written in shells or energy levels such as 2 , 9 , 1 is called the electron arrangement • The writing of the organisation of the electrons in sub-shells (e.g. 1s2 2s2 2p3) is called the electronic configuration

  15. Electronic Configuration • List of subshells containing electrons

  16. Electronic Configuration • List of subshells containing electrons • Written in order of increasing energy

  17. Electronic Configuration • List of subshells containing electrons • Written in order of increasing energy • Superscripts give the number of electrons

  18. Electronic Configuration • List of subshells containing electrons • Written in order of increasing energy • Superscripts give the number of electrons Example: Electron configuration of neon number of electrons 1s2 2s2 2p6 main shellsubshell

  19. Filling sub-shells • The order of filling the sub-shells becomes more complex at higher energy levels as the energy levels/shells start to overlap • From itl.chem.ufl.edu/2045_s00/lectures/lec_11.html

  20. To help you remember From: itl.chem.ufl.edu/2045_s00/lectures/lec_11.html

  21. You need to be able to write electronic configuration for the first 54 elements E.g. H(1) 1s1 Li(3) 1s2 2s1 Ne(10) 1s2 2s2 2p6 Na (11) 1s2 2s2 2p6 3s1 Write out electronic configurations for: Be, O, Mg, P, Cl, Mn, Zn. Ge, Br, Sr, Ag and I. Writing Electronic Configurations

  22. Answers • Be - 1s2 2s2 • O - 1s2 2s2 2p4 • Mg - 1s2 2s2 2p6 3s2 • P - 1s2 2s2 2p6 3s2 3p3 • Cl - 1s2 2s2 2p6 3s2 3p5 • Mn - 1s2 2s2 2p6 3s2 3p6 4s2 3d5 • Zn - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 • Ge - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2 • Br - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 • Sr - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 • Ag - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d9 • I - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5

  23. Shorthand Electronic Configurations • To save writing out all the lover level configurations, it can be shortened by building on the last noble gas configuration • E.g. Na 1s2 2s2 2p6 3s1 or [Ne] 3s1 or K 1s2 2s2 2p6 3s2 3p6 4s1 or [Ar] 4s1

  24. Shorthand Electronic Configurations • To save writing out all the lover level configurations, it can be shortened by building on the last noble gas configuration • E.g. Na 1s2 2s2 2p6 3s1 or [Ne] 3s1 or K 1s2 2s2 2p6 3s2 3p6 4s1 or [Ar] 4s1 For all elements on the previous slide, write their electronic configurations in the shorthand form

  25. Orbitals • A 3-dimensional shape/area outside the nucleus where there is a high probability that electrons can be found • s orbitals are spherical in shape • p orbitals are shaped like a peanut • d orbitals are doughnut-shaped

  26. From: www.chem.queensu.ca/.../orbitals/index.htm

  27. Filling Orbitals • Each orbital can contain a maximum of 2 electrons with opposite spins • This can be shown diagrammatically using either lines or boxes and arrows - From: http://www.xmission.com/~seldom74/chem1110int/ch03/03i.htm

  28. Hund’s rule • This diagram is also based on Hund’s Rule • Orbitals within the same subshell are filled singly first • This reduces the amount of repulsion by having two electrons in the same orbital

  29. Question • Draw diagrams using lines to represent orbitals and arrows for electrons to represent: • F • Na • P • S • Ar • Al

  30. Aufbau Principle • The writing of electronic configurations is based on the Aufbau Principle, which states that orbitals with the lowest energy are filled first

  31. Electronic Configuration & the Periodic Table • The structure of the periodic table is related to the subshell electronic configuration • s block has s1 or s2 in its outer shell • p block have p1 to p6 in their outer shell • Transition metals have d1 to d10 in their second last shell • From the electronic configuration can work out the group and period

  32. From: http://www.xmission.com/~seldom74/chem1110int/ch03/03i.htm

  33. Question • What period, block and group are the following elements in? • 1s2 2s2 2p1 • 1s2 2s2 2p6 3s2 • 1s2 2s2 2p6 3s2 3p6 4s1 • 1s2 2s2 2p6 3s2 3p6 4s2 3d5

  34. Question • What period, block and group are the following elements in? • 1s2 2s2 2p1 Period 2, p block, Group 3 • 1s2 2s2 2p6 3s2 Period 3, s block, Group 2 • 1s2 2s2 2p6 3s2 3p6 4s1 Period 4, s block, Group 1 • 1s2 2s2 2p6 3s2 3p6 4s2 3d5 Period 4, d block, transition metals

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