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Name: _______________________________________________ Date: ____________________ Period: ___________
Electron Configuration Worksheet
In the space below complete the electron configurations for the following elements in Period 4 in the Alkali Metals
group and the noble gases:
Period 4:
K:
1s22s22p63s23p64s1
Alkali Metals
Li:
Ca:
Na:
Sc:
Rb:
1s22s22p63s23p64s23d3
V:
Cs: 1s22s22p63s23p64s23d104p65s24d105p66s1
Mn:
Co:
Noble gases
Zn:
He:
Ga:
1s22s22p63s23p64s23d104p1
Ar:
Se:
Kr:
Br:
Xe
Kr:
1s22s22p63s23p64s23d104p6
Questions:
1. Which groups ended in a “s” orbital?
2. Which groups ended in a “p” orbital?
3. Which groups ended in a “d” orbital?
4. The “s” block contains which families of metals? Which is group 1? Which is group 2?
5. What is another name for the “d block” elements?
6. What is another name for group 17?
7. What is another name for group 18?
Notes: Atoms react based upon their valence electrons. Valence electrons are the outermost electrons from the
nucleus. The periodic table allows us to determine the number of valence electrons an element has based on its
position on the table.
Group 1 elements have 1 valence electron,
Group 2 have 2,
Group 13 have 3
Group 14 have 4
Group 15 have 5
Group 16 have 6
Group 17 have 7
Group 18 have 8.
The transition metals (Groups 3 – 12) do not follow this rule.
8. Based on your answers to questions 1 – 8, and the notes above, complete the following table
Element
Potassium
Calcium
Gallium
Germanium
Argon
Arsenic
Selenium
Bromine
Krypton
Lithium
Sodium
Rubidium
Cesium
Symbol
Last Electron Level Orbitals
4s1
Group #
1
# Valence Electrons
2
13
4s2 4p2
15
4s2 4p4
17
7
2s1
1
6s1
1
Notes: All elements seek to behave like the noble gases (group 18) with a full valence shell of 8. Atoms either get rid of
or take electrons to get to this magic number. Metallic elements of 3 or less valence electrons give up their electrons (low
electronegativity) and to resemble the electron configuration of noble gas that is behind them on the periodic table. For
example, Indium (In) is in group 13. It has 3 valence electrons (5s24d105 p1: 2+1=3). It is a metal and has less than 4
valence electrons so it will give up its electrons. When an element gives up electrons, it becomes positively charged (+)
by the same amount of electrons it gives up.
Example: In gives up 3 electrons = it becomes a 3+ ion. So the ion would be written In3+