EXPLAIN Introduction to and Organization of the Periodic Table

​How useful is the periodic table in our lives?

The Periodic Table of Elements helps us better understand chemical elements and their relationship to one another. The products, materials and technologies that shape our lives are created by the elements and how they react with one another. ​

(Source: www.chemicalsafetyfacts.org/)

The periodic table is an important tool to students and chemists, because it puts all the known elements into a meaningful pattern.

The periodic table is organized into

• columns called groups or families​

  • based on increasing atomic number​

• rows called periods

It is important to remember that the periodic table is arranged by increasing atomic number, from left to right.

Atomic Number:​

• is the number of protons​

• gives the element its identity

Groups

• vertical columns on the periodic table numbered 1-18 ​

• commonly referred to as families ​

• Elements in the same group have…

  • similar physical and chemical properties ​

  • the same number of electrons in outer most shell (valence electrons)

Physical Property

• is a characteristic that can be observed with our 5 senses, or measured

• ​Examples: ​

  • color, size, shape, and texture​

  • phase, and melting and boiling points ​

  • density, solubility, odor, etc. ​

Chemical Property

• is the ability or inability to change from one substance to another ​

• dependent on the number of valence electrons

• ​Examples: ​

  • combustibility and flammability ​

  • toxicity and reactivity ​

  • acidity and corrosivity

Periods

• horizontal rows on the periodic table

  • numbered 1-7 ​

• periods tell scientists the number of electron shells or energy levels an element has​

  • energy levels hold the valence electrons

Use the last few slides to summarize the information you learned today, and to reflect on your learning.

In Summary

The periodic table lists only elements, and not compounds or mixtures.​

The elements are ordered by their atomic number.

• horizontal rows​

• elements in the same period have the same number of energy levels

Periods:

• vertical columns​

• elements in the same group have similar properties

​Groups:

Thank you for completing your notes.

• Glue your notes sheet into your notebook.

Reflect - are you able to do the following:

• recognize that an atom’s identity is related to the number of protons in its nucleus ​

• describe the organization of the periodic table in terms of atomic number, and groups vs. periods ​

• recognize that the number of electrons in the outermost energy level determines an element’s chemical properties or chemical reactivity