4.06 Periodic Table of Elements
My Goals for this Lesson: Explain how the periodic table is organized.
Use the periodic table to obtain information. What: How would you arrange the breakfast cereals in a grocery store to make them easier to find? Try the activity.
Why: Mendeleev’s Periodic Table
Organizing the elements How did Mendeleev organize the 63 known elements in his table?
He started by organizing the elements by their mass in ascending order. How was he able to “predict” discoveries of elements in the future?
When elements were arranged in order of their mass, he noticed that their physical properties repeated periodically in a regular, predictable way.
How did the discovery of atomic numbers help to shape the periodic table we have today? Why was this discovery important?
Modern Periodic Table What important information is found in today’s periodic table: 1. Element name and symbol
2. Atomic number (numbers of protons in each atom)
3. Average atomic mass
4. Physical properties: metal, non-metal, or metalloid
5. Electrons locations and reactivity of elements. Metalloid – Elements that contain properties of both metals and non-metals. Atoms from elements in columns share similar physical properties, but also tend to react with other elements in similar ways. Because of these similarities, the columns are also referred to as “families.” Scientists can use information from the periodic table to study how elements behave.
The periodic table shows patterns in the following electron properties
An element’s row number is also the number of: energy levels its electrons occupy.
Valence electrons are located in: the outer most energy level of an atom.
Valence electrons are involved in: chemical bonding
Atoms of elements in the same column share the same number of: valence electrons
Electronegativity is: an atom’s ability to attract electrons and form chemical bonds
The greater the electronegativity: the greater the ability of an atom to bond with another atom
An atom's electronegativity increases as you go across from: left to right on the periodic table and move up the periodic table.
Check out the Periodic Table in the lesson Describe the general trends you see for the following categories: Metals/non-metals/metalloids: A periodic table is shown. Different colors indicate elements that are metals, nonmetals, or metalloids. The following elements are nonmetals: hydrogen, helium, carbon, nitrogen, oxygen, fluorine, neon, phosphorus, sulfur, chlorine, argon, selenium, bromine, krypton, iodine, xenon, and radon. The following elements are metalloids: boron, silicon, germanium, arsenic, antimony, tellurium, and astatine. All of the other elements are metals.
Electronegativity: is an atoms ability to attract electrons and form chemical bonds. The greater the electronegativity, the greater the ability of an atom to bond with another atom. An atoms electronegativity increases as you go across from left to right on the periodic table.
