Online College Courses for Credit

Periodic Table

Periodic Table

Author: Christy Morley

Understand the physical and chemical properties of atoms based on their position on the Periodic Table.

Students should be able to identify groups, periods, metals, metalloids, nonmetals and transition elements. Students should be able to compare the: atomic radius, reactivity, electronegativity and ionization energy of 2 atoms.

See More
Fast, Free College Credit

Developing Effective Teams

Let's Ride
*No strings attached. This college course is 100% free and is worth 1 semester credit.

29 Sophia partners guarantee credit transfer.

311 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 27 of Sophia’s online courses. Many different colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.



Source: Created by C. Morley in Active Inspire

Introduction to the Periodic Table

A description of the groups in the periodic table and where they are located (does not include s,p,d,f labels)

Source: Created by C. Morley on iPad

Periodic Table Arrangement

The periodic table is arranged according to increasing atomic number. This unit looks at the patterns that exist when the elements are arranged that way.


Every element in a given row or period has the same number of electron shells or energy levels (recall the Bohr diagram circles). Otherwise, the elements in a row do not share any common characteristics. The row an element is in cannot tell you much about how those atoms will behave. We do know that elements in the same row get smaller as you move to the right. This is because those elements are pulled in by the protons in the nucleus. Because the element has not added any more energy levels, the protons do not have to reach any further and can actually pull the energy level in closer.


Elements that are in the same column or group share the same number of valence electrons. Valence electrons are the number of electrons in the outermost energy level. This is extremely important to know because the number of valence electrons that an atom has is going to determine how the atom behaves. Several groups (1,2, 17 and 18) are also considered to be families, because they have some unique characteristics in common. An element’s group will tell you much more about the element than the period will.


For certain groups, looking at the number above the group will give you a hint as to how many valence electrons that group has. For example, the elements in group 1 will always have 1 valence electrons (their electron configurations will always end in ns1 where n is the energy level that element is in). The transition metals do not follow this rule very well, but the first 2 columns and the last 6 columns follow it perfectly. For groups 13-18, you only look at the last number in the group number. So the elements in group 14 have 4 valence electrons. You need to know how many valence electrons an element has to draw a Lewis Dot Diagram.


The valence electrons are the only electrons that an element uses to create bonds. Bond breaking and bond forming is how chemical reactions occur, so we need to understand how this happens. Our next unit will go into detail about bonds but this will help us better understand that unit. When you draw a Lewis dot diagram, there are 4 spots that can be used to draw electrons. If you imagine that the element symbol is like the face of a clock then we can draw the electrons at 12 o’clock, 3 o’clock, 6 o’clock and 9 o’clock.  We draw electrons alone first and then pair them up if we need more space. Generally, all atoms want to get 8 valence electrons around them (this is called the Octet Rule).


Answer each of the following questions in complete sentences.


How is the periodic table arranged?
What do we call the horizontal rows on the periodic table? What do all of the elements in a row have in common?
What do we call the vertical columns on the periodic table? What do all of the elements in a column have in common?
Which tells us more about an atom: the row or the column? Why is that?
Which of the following elements is Chlorine (Cl) most similar to? Explain why.      a) F b) S c) O d) Ar 

Source: Created by C. Morley on Word for Mac

Periodic Table

Source: Created by C. Morley

Periodic Trends

Looks at atomic radius, ionization energy, reactivity and electronegativity.

Source: Created by C. Morley on iPad