Electron Arrangements and the Periodic Table

1
Electron Arrangements and the Periodic Table

• Chapter 11. Sections 11.9-11.11

2
Review

• So what caused the different spectrums of the
  different elements in the lab on Friday?

3
Electron Configuration

• When describing the ground states of various
  atoms, with different amounts of electrons, we
  call the placement of their electrons in energy
  levels, sublevels, and orbitals their Electron
  configuration.
• We can state this electron configuration two
  ways
• Configuration
• Orbital Diagram

4
Electron Configuration cont

• For example
• Hydrogen in its ground state has 1 electron in
  the 1s energy level/sublevel/orbital
• This could be represented as

5
Electron Configuration cont

• Another example
• Helium 2 electrons on the 1s energy
  level/sublevel/orbital

6
Electron Configuration cont

• Lets try one that is pretty big comparatively
• Boron has 5 electrons
• So it has 2 electrons on the 1s, 2 electrons on
  the 2s, and 1 on the 2p

7
Electron Configuration cont

• So how do we add to the p orbitals
• Lets see with carbon!
• What about Oxygen?

h
i
8
Electron Configuration cont

• So lets try the ground state of
• Magnesium 12 electrons!

h
i
h
i
h
h
i
i
h
i
h
i
9
Orbital filling the rules

• You know, in a perfect world (perfect for
  chemistry students, anyway), you'd take all those
  little electrons, start with a 1s orbital, and
  work your way up in numerical order (1s, 2s, 2p,
  3s, etc). But Noooooooooo,. What actually happens
  is once you start putting electrons in those
  orbitals, they don't keep the order they were in
  after 3p. This is because once you add electrons
  to orbitals, their energies change and causes a
  lot of criss-crossing. The actual order for
  filling in electrons is
• 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s,
  4f, 5d, 6p, 7s, 5f, 6d, 7p, 8s, etc.
• Oh no, MEMORIZATION! No, lucky for us - yes,
  myself included - there have been a couple of
  memory aids designed to help keep these things in
  line.

10
Orbital filling the rules
11
Orbital filling the rules

• Lets try Calcium!
• ___ ___ ___ ___ ___
• ___ 3d 3d 3d 3d 3d
• 4s
• __ __ __
• __ 3px 3py 3pz
• __ __ __ 3s
• ___ 2px 2py 2pz
• 2s
• ___ 1s

h
i
h
h
h
i
i
i
h
i
h
h
h
i
i
i
h
i
h
i
http//intro.chem.okstate.edu/WorkshopFolder/Elect
ronconfnew.html
12
Orbital filling the rules

• If the principle energy level has d orbitals, the
  s orbital form the next level fills the s level
  of the previous energy level first
• After lanthanum, the lanthanide series occurs to
  fill the seven 4f orbitals
• After actinium, the actinide series occurs to
  fill the 5f orbitals
• Expect for He the group numbers indicate the
  highest principal energy level on the s or p
  level. These are the valance shell.

13
Partial electron configurations for the
elements potassium through krypton.
14
Orbitals being filled for elements in various
parts of the periodic table.
15
Periodic table with atomic symbols, atomic
numbers, and partial electron configurations.
16
Atomic properties and the periodic table

• By looking at the orbitals, we can get general
  properties of the elements on the periodic table.
• Such as ionization energy decreases as you move
  down a family.

17
Classification of elements as metals, nonmetals,
and matalloids.
18
Relative atomic sizes for selected atoms.
19
Homework

• Read pages 339-353. Problems 1-6 on page 352, 37
  and 55 on page 355-7