The Periodic Table

 Go to page 154  Complete the Inquiry Activity.  You have 10 minutes to construct the table and answer the corresponding questions.  You will be expected to share your answers so please complete all parts of the procedure and ‘Think About It’.

Chemists used the properties of elements to sort them into groups. Mendeleev, a Russian chemist, was credited with constructing one of the first periodic tables. – He arranged the elements according to increasing atomic mass. – He was able to give justification for placing elements in certain places according to similar chemical properties.

Mendeleev constructed his periodic table before the internal structure of the atom was known. – He did not know that atoms had a specific number of protons. In the modern periodic table, elements are arranged in order of increasing atomic number. The elements in a group have similar properties. As you move from left to right across a period, properties gradually change. The patterns repeat when you begin a new row (period). – This is referred to as periodic law.

 The International Union of Pure and Applied Chemistry (IUPAC) is an organization that sets standards for chemistry. The groups are numbered 1 – 18. The elements can be organized into three categories: metals, nonmetals and metalloids. Across a period, elements gradually move from metals to nonmetals.

 Most elements are metals  Good conductors of heat and electricity,  Shiny (due to its ability to reflect light),  Solids at room temperature (except Hg),  Ductile,  Most are malleable.  Ex. Cu, Ni, Na, and Mg.

Most are gases at room temperature, Poor conductors of heat and electricity (C is an exception), Tend to be brittle. Ex. Cl, Br, H, Ne They do not tend to follow the same rules for sharing characteristics with other nonmetals, like metals do.

 Share characteristics of metals and nonmetals.  Differing conditions afford them the ability to behave like metals or nonmetals.  Chemists do not always agree with which metalloids should be named.

 Page 160.  Questions 5 – 7 in your notebook. Be prepared to answer the questions orally.

 The periodic table displays the symbols and names of the elements, along with information about the structure of their atoms.  Group 1A metals are called alkali metals.  Group 2A metals are alkaline-earth metals.  Group 7A are halogens.

 Since electrons play a role in the properties of elements, it makes sense that electron configurations within groups be similar.  Elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals according to their electron configurations.

 Examine the electron configuration of the noble gases on page 164 – what do you notice?  The s and p sublevels are filled with e-  Does it make sense that the principal quantum number changes with each noble gas?

 All of the groups with the letter A in the group name are representative elements.  How does the group number appearing before the letter A compare to the electron configurations of those corresponding elements?  The group number corresponds with the number of e- in the highest orbital.

 The transition elements belong to the B group. There are two groups – transition and inner transition.  The transition are those in the main block of the periodic table. The highest orbital they begin to fill is “d”  The inner transition begin to fill the “f” orbitals.

 Page 167.  Questions 10 – 15.