How to Read the Periodic Table (Physical Properties)

METALS AND NONMETALS

This section expands on the Introductory section and Electron Configuration section that started the process of reading the Periodic Table {Families (columns) and Periods (rows)}. The next level of organization to be mentioned it that of metals and nonmetals.

Using your current Internet browser, open a second window.  In Chrome, Firefox, and Safari, under the “File” drop down menu there is a ”New Window” choice.  Click this to open a new window.  Copy and paste the following address:  (http:// www.ptable.com/#) and be sure the left hand tab has Wikipedia in it.  The table should be wide enough to show:

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The student should have two windows open.  One showing this discussion and another showing the Periodic Table.

Below the column numbers in the middle of the window is an arrangement titled Nonmetals and Metals.  These headings are subdivided into additional smaller units.

Metals consist of Alkali metals, Alkaline earth metals, Lanthanoids, Actinoids, Transition metals, and Post-transition metals.

Move your cursor over the title Metals to highlight those elements that are metallic. Metals are found left side and occupy most of the Periodic Table.

Move your cursor over each of the names under the Metals heading to highlight where each of the Families is found.

Column 1 elements have the Family name of Alkali metals and Column 2 elements have the Family name Alkaline earth metals.  The remaining columns do not have a designated name, but are sometimes identified by the name of the first element in the column.

Move your cursor over the title Nonmetals to highlight the remaining elements that are nonmetals. The subcategories Nonmetals are: Other nonmetals, Halogens, and Noble gases.  Column (18) on the right is labeled Noble gases.  The elements in Column 17 have the Family name Halogens.  The remaining nonmetals are found at the tops of Families 14, 15, and 16.

The metalloids are between metals and nonmetals.

Learn the placement of the metals and nonmetals and the names of the families.  This information will be used in future discussions.

ACTIVITY 1: PHYSICAL PROPERTIES
This activity is designed to learn where elements are placed and to observe physical properties of selected elements.

Click on the Homework tab to access a Metals Table and a Nonmetals Table.  Click on each of these and print them out.

In the Periodic Table window, double click on the first element (Li) in the metals table.  A window will appear with text on the left describing the element.  On the right is a picture of the element.  Below the picture is a table of General and Physical properties.  Enter the information for Li in the table.

One may need to use the scroll bar on the window to scroll down to find the melting point, boiling point (in Celsius,C) and the atomic radius for each element.

Repeat for each element in the Metals Table.

Use the Nonmetals Table to enter information for the elements listed.

Your list should indicate metals are solid and have luster, while nonmetals are mostly gases and non-luster solids.

ACTIVITY 2: PHYSICAL STATE AS A FUNCTION OF TEMPERATURE
The Periodic Table used above should still be open.  There is a temperature slider on the top upper right side extending just below column number 13 to just below column number 16. The value in the window on the right side of the slider should be 273.  If it is not click on the number, use the up or down arrows to change it to 273.  273 Kelvin is equal to zero Celsius.  The physical state of each element is indicated by the color code on the top left near the alkaline earth Family.

Observe that most of the elements are solids, eleven are gases, and two are liquids at the temperature given.  All the metals are solids except mercury (Hg).  The Noble gases (column 18) and the elements at the top of columns 14, 16, and 17 are gases.  Bromine is the only nonmetal that is a liquid.

Move the temperature slider to the left to its lowest value.  Zero should appear in the window.  This temperature value is referred to as absolute zero, the point at which there is no heat energy.

Observe the physical states of the elements.  Helium is the only element that is not a solid.  Find the boiling point of Helium from the table of properties you prepared earlier.  It should be -268.9 C.  This temperature is little over 4 degrees higher than absolute zero.   Click the up arrow in the temperature window to change the temperature up by one degree.   Click on the up arrow until He changes from a liquid to a gas. The change should be between 4 degrees and 5 degrees.  At this temperature  a physical state change from liquid to a gas occurs.  The temperature at which this occurs is called the boiling point.

At this temperature (- 268.9 C) the remaining elements are still solids.  Click the slider and move it up until the physical state of one of the other elements changes.  What is the element and what is the physical state to which it changes?

You should observe the element Ne changing from a solid physical state to a liquid physical state.  The temperature at which this occurs is the melting point for Ne.

Check for one more physical state change by clicking the slider and moving it up to increase the temperature reading.  Tell the physical state change and the temperature at which the change occurred.

Increase the temperature slowly by moving the slider to the right.  Note changes that occur.  Stop when the temperature reading is 273 Kelvin.  You may need to use the up/down arrows to get to 273.

Continue moving the slider slowly to the right and watch as each element undergoes a physical state change with added heat energy (increase in temperature).  Pay attention to which metal families change from a solid to a liquid first.

Move the temperature slider back to 273 K and observe changes in the nonmetals as the temperature decreases  (heat is removed).

Why are elements solids, liquids, or gases at normal temperatures?
To start this discussion, set the temperature reading to 25 degrees Celsius ( 298 K).

All the elements are solids at 25 deg Celsius except mercury (Hg) and bromine (Br) that are liquids and hydrogen (H), nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), and the Noble gases in Family 18 that are gases.

The strength of attraction between atoms in an element determines the physical state of an element.  If the attraction between atoms is strong, the element will be a solid.  If the attraction is less strong, the element will be a liquid.  If the attraction is weak, the element will be a gas.

Metal Solids
Metals have valence electrons farther from the nucleus resulting in these electrons being less attracted to the nucleus.  The valence electrons are able to locate between many metal atoms forming a sea of electrons.  These valence electrons are said to be delocalized meaning they are more spread out.  The attraction between the slightly more positive nucleus and the sea of electrons creates a strong interaction or bond. This strong bond holds the metal atoms closer together forming a solid state.  The bonds between metal atoms are referred to as metallic bonds.  See the video metallic bonds.

Noble Gases
The Noble gas elements are gases at 25 deg C (298 K).  This implies there is very little attraction between the atoms of these elements.  Helium atoms have very little attraction for other Helium atoms.  Neon has very little attraction for other Neon atoms.  The same is true for the remaining Noble gases.

An important observation is that Noble Gases have a very low reactivity with other chemicals at 25 degrees C.  They don’t react with oxygen, water, or a host of other commonly occurring chemicals. They exist in nature as individual atoms.  How can this be explained?

The Noble Gas family is the only family in the Periodic Table to have every orbital in every primary energy level filled with two electrons. Atoms with completely filled primary energy levels are very stable.  Valence electrons are held very tightly by the noble gas atoms which limits attraction to atoms of other chemicals and lowers their chemical reactivity.

Diatomic gases
The remaining nonmetal gases (N, O, F, Cl) do not exist in nature in the atomic state.  They exist as diatomic molecules (N2, O2, F2, Cl2).  A molecule is neutral group of at least two atoms held together by covalent bonds.

These elements are gases at 25 deg C because there is very little attraction between the molecules of these elements.

An interesting observation is that Br and I also exist as diatomic molecules, but Br2 is a liquid and I2 is a solid at room temperature.

Click the link Covalent Bonds for further discussion

Isotopes
All atoms of an element are not identical; they differ in their mass.  The difference is due to the presence of neutrons.   A neutron is an uncharged particle found in the nucleus of atoms that has a mass approximately equal to the mass of a proton.  Atoms of the same element with different masses are called isotopes.

The You tube video Protons, neutrons, electrons and isotopes provides a good graphic discussion of isotopes.

The Dynamic Periodic Table has a good way of showing the isotopes of an element and information of each of the isotopes.  Using your current Internet browser, open a second window.  In Chrome, Firefox, and Safari, under the “File” drop down menu there is a ”New Window” choice.  Click this to open a new window.  Copy and paste the following address http://www.ptable.com/# into the address bar.  When the Periodic Table appears, click on the “Isotopes” tab.  Keep both windows open as you read the following.

Click on the element hydrogen.  Three square boxes will appear on the bottom right.  These boxes indicate the three isotopes of hydrogen.  Move your mouse over the top of the three boxes and observe the information that appears to the immediate right especially the abundance.  The 1H isotope of hydrogen makes up 99.985% of all the hydrogen in the world.  Move to the next box and observe the abundance of 2H isotope.  Move to the third box and observe the abundance 3H isotope.  This isotope is radioactive .   If you click on any of the isotope boxes additional information regarding that isotope will appear.

Select several other elements and observe the number of isotopes they have and the relative abundance of the isotopes.

The atomic weight of the atoms of an element is an average of the weights (masses) of the isotopes of that element.

Radioactivity is an important and interesting phenomenon, but we will not discuss it in this course.