Title: Periodic Table Shortcut Noble Gas Notation Lewis Dot Structures
1Periodic Table ShortcutNoble Gas NotationLewis
Dot Structures
2When we write electron configurations, do we need
to always start at the beginning?
- No, there are a few shortcuts.
3The first shortcut involves the placements of
elements on the periodic table
- Let us look at the electron configurations from
yesterdays homework and bell work from today and
see how they fall on the periodic table. - You will need 4 color pencils for this.
4So, the periodic table is arranged with electron
configurations in mind
5The rows and columns
- The rows correspond to the principle quantum
number (n) - In other words, each time you drop a row on the
periodic table, you go out an energy level. - Be careful with the d and f areas
- The d area is n-1 and the f area is n-2
- La and Ac are considered the first f area
elements - The sets of columns correspond to l quantum
numbers and the amount of electrons in that
orbital
6So, by looking at the periodic table, one can
find an elements electron configuration
7Lets try some examplesRemember it should be a
number then a letter then a superscript
- What is the last orbital of tin (Sn)?
- What is the last orbital of Ruthenium (Ru)?
- What is the last orbital of Holmium (Ho)?
- What element ends with the electron configuration
of - 5s1
- 6p4
- 5f3 (remember Ac is first f)
8The second shortcut
- We need to find a group of elements that have
completed or full orbitals. - That group is the noble gases.
- The last column on the periodic table.
- This group can be used to write an abbreviated
version of an elements electron configuration.
9Lets look at yesterdays homework again
10How to write Noble Gas Notation
- Find the closest _________ noble gas to the
element in atomic number without going over. - Write that noble gass symbol in brackets.
- Go back to the beginning of the row and work back
to the elements writing down the orbital sections
and counting the electrons as you go.
11Examples
- As (Atomic Number 33)
- What is the closest Noble gas without going over?
- Ar
- So, Ar
- C
- He2s22p2
- Pb
- Xe
4s2
3d10
4p3
6s2
5d10
6p2
4f14
12Lewis Dot Formulas
- Shows the valence electrons of an atom
- Valence electrons are the electrons in the
outermost energy level - The only electrons that are in the outermost
energy level are s and p. - Therefore, the most valence electrons an atom can
have is 8 (2 from the s and 6 from the p).
13Lewis Dot Formulas
- So, Lewis Dot Formulas are the chemical symbol
surrounded by dots. - There will be one dot per electron in the s and p
orbital - Hunds rule must be followed
14What is the Lewis Dot Structure for the following?
- Francium
- Arsenic
- Hydrogen
- Krypton
- Oxygen