The Periodic Table

The Periodic Table organizes all known elements into rows and columns. Rows are called periods and columns are called groups. In the current table, there are 7 periods and 18 groups.

The period organization is based on specific energy levels of atoms, which includes particular quantum numbers that deal with electron orbitals and the ‘legal’ spaces they’re allowed to occupy.

The elements in columns share common traits based on their subatomic makeup, and you’ll learn how to recognize some patterns in both.

Each element in the table has information provided – some tables are more detailed than others but at a minimum, one normally sees the atomic symbol, the atomic number (# protons), and the atomic mass (weighted average of all known isotopes.

If there is room, you might see the element’s name, electron configuration, oxidation states, or other information. Many include a color scheme to denote their physical state and type.

Most elements are solid, several are gases, and two are liquids (Br, Hg).

Most elements are metals (shiny, malleable, conductive)
Some elements are nonmetals (dull, poor conductors)
A few are metalloids (possess both metal and nonmetal properties).
All elements with atomic numbers >83 are radioactive.
All elements with an atomic mass in parentheses are man-made and have no natural isotopes.

Main Group Elements

Groups 1, 2, and 13-18 (8 total groups) are the main-group elements. These are the elements we’ll work most with during the semester.

Alkali and ALkaline Metals

The first group (1) are called alkali metals. though hydrogen is not a metal, it does have some commonalities with the metals below it, which we’ll learn later.

The second group (2) are the alkaline earth metals.

Group 18 elements are called noble gases.
Group 17 elements are called halogens.
Group 16 are chalcogens.
Group 15 are pnictogens.

Transition Metals

Groups 3-12 are called transition metals, including the bottom two rows called inner transition metals.

The top row of inner transition metals are lanthanides, and the bottom row are actinides.

In Summary

Review/try problems 37, 39, 41, and 43

QUESTIONS ?