Periodic Chart of the Elements iPad app

This app shows the Periodic Table of the Elements, which most certainly hung on the wall of your high school chemistry class. But, instead of showing all the information for an element stuffed into one small incipherable square, you select a chemical trait and the entire chart becomes color coded to show how the range for that trait varies across all elements.
When an elements symbol in the table is clicked on information about it appears in the upper left of the screen, and a simplified diagram of its electron shells appears in the upper right. Being able to view the electron shells like this allows the student to better understand how the electron configuration, along with the radius of the outer shells, control the chemical properties an atom has.

Reviews: At least three independent reviewers consider this app a 'must have' for educators and students.
This shows the table in its most common color scheme - all elements in the same family are shown in the same color. But notice the radio bar along the bottom of the chart. You can can select a different chemical attribute to color-code the chart.
  • Number - color codes the chart to show how the atomic number increases left-to-right, top-to-bottom.
  • Group - (shown to the left) - all elements in the same family are shown the same color.
  • Metal - shows which elements are metals, non-metals or metalloids.
  • Electronegativity - a measure of an atoms reactivity.
  • Radioactivity - a measure of how quick an atom wants to rip itself apart.
  • Melting Point
  • Boiling Point
  • State - whether an element is a solid, liquid, or gas. When this option is selected the Temperature slider control is activiated. You can change to any temperature you wish and the chart will update to show the state of elements at that temperature.

The chart showing the Metal color coding.

The chart with the Electronegativity color coding.

The chart with the State color coding. You can move the Temperatur slider and watch the elements go from solid to liquid to gas as their melting and boiling point temperatures are passed, and then back from gas to liquid to solid.

The More Information screen gives even more information about elements. Care has been given to explain the origin lf those symbols such as Pb that are obviously not derived from the elements name. This makes chemistry a little more interesting and has always been a point of confusion for students.

Instructional Features

  1. A simplified electron diagram is displayed for each atom when they are selected. Since the electron configuration and the relative size of the atom are determining factors for chemical properties this is very useful.
  2. When attributes such as radioactivity are selected the coloring scheme is kept very simple so the trend of that attribute across the Periodic Table is easy to see.
  3. The origin of the name and the symbol are included in the details for each element. These tend to be the most commonly asked questions about atoms.

Some suggested activites

Tap Number and the periodic table will recolor with a blue gradient, the lightest elements being pale blue and the atoms with the higher atomic weights a darker blue.
Now tap Group and the various families, or groups, of elements will have the same color. Now, tap different elements within the same family and watch the diagram of the electrons.
Do you notice how all the atoms within a group have similar patterns?
But you may notice two of the families - the Rare Earth Metals and the Actinide Metals do not follow this pattern. Any idea why?
Students may notice the Rare Earth Metals and Actinide Metals are HUGE and this is the reason. Indeed, there are two main factors that determine an atoms chemical properties.
  1. The pattern of the electrons (or the 'holes') in the outer shell
  2. The size of the atom, and hence the distance from the neucleus to the outermost shell.

Now tap Metal to see which atoms are metals, which are non-metals, and which are undecided on the matter.
Metals allow electricity - electrons - to move freely. What do you think determines whether or not an atom is metalic?
Students may notice that non-metals tend to have a combination of more electrons than holes in the outer shell, and have an outer shell that is rather small. Both of these factors could contribute to the atom 'grabbing' and electron tightly, and not letting it move one.
Now tap E.N.. E.N. stands for electro-negativity, which is a measure of how chemically reactive an element is.
Why do the noble gases have zero electronegativity? Why does Flouride have such a high value?
The noble gases have completely filled out shells. Flouride needs only one electron to fill its outer shell, and that shell is very close to the neucleus so the attraction of an electron that fills that hole will be very great.
Now tap Radio. Radio stands for radioactivitity. What seems to be the main factor that determines if an element is radioactive?
Students will probably notice that heavy elements tend to be radioactive. Indeed, as the neucleus gets filled with protons and neutrons it gets so large it becomes unstable. But students will probaly notice that this is not a direct relationship. Notice that while Radon is very radioactive the elements immediately adjacent to it - Astatine and Francium - are much more radioactive. Why is this? Only a scientist can tell for sure, but notice that Radon is a Noble Gas and has a very stable configuration of electrons. Very possibly the proton configuration in the neucleus is similarly stable. Or maybe that stable 'cloud' of electrons results in consistent attraction on all protons, and removing or adding an electron makes this less consistent.
Tap Melt and Boil to see the relative Melting and Boiling Points.
Tap State to see the states of the elements - Solid, Liquid, or Gas. Now move the Temperature slider left to right to see how elements first melt and then boil as the temperature rises.
Do you notice there is a slight tendency for non-metals to melt and evaporate quicker than metals? Does this have any significance?
Salts consist of atoms of metals and non-metals bound together. All living things have some (small) amount of salts in them. When things burn and the temperature gets high enough for molecules to tear about, there will be a slight tendency for a larger portion of non-metals to become and stay gaseous than their non-metals partners. And then, when non-metals in the atmosphere combine with water they form weak acids, and metals left in the ashes will combine with water to form weak alkalines.

About the programmer
Kevin Neelands lives in Gainesville, Florida (home of the fightin' gators) and gets his kicks writing silly little programs. He was known as the 'mad scientist' of third period after a chemistry experiment went bad.