# Elements by Their Uses

#### January 19, 2017

Keith Enevoldsen has an excellent version of the periodic table that has some of the more popular uses of the elements on them.

Hat tip to Ms. Douglass for this link.

Citing this post: Urbano, L., 2017. Elements by Their Uses, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

# Patterns in the Periodic Table

#### January 16, 2013

The rapid increase and slow decline of atomic radius repeats itself every 8 elements in the first 20 elements.

Why is the periodic table called the periodic table? Because of the periodic changes in the properties of the elements: there are patterns to the properties that repeat, time after time, as you go through the sequence of the elements. One key repetition, which affects the way different elements react, is in the electron configurations, however, other properties change as well. In fact, history of the periodic table
is a story of scientists trying to figure out the properties of unknown elements (not to mention figuring out that there were undiscovered elements) based on what they knew about the periodicity of the known elements.

In this exercise, we look at four different properties that students need to be aware of: density, melting point, ionization energy, and electronegativity. I’ve compiled the data in this spreadsheet: periodic-table-properties.xls; and I handed out the first page, with the properties of the first 38 elements (periodic-table-properties.xls.pdf).

The repeating pattern in electronegativity shows up quite well in the first 20 elements.

I broke the class into pairs and had each pair graph one of the four sets of data. With 16 students that meant that we had a replicate of each graph, so I could use the redundancy as a quick check that they’d done them correctly.

The pattern with density is harder to discern, but it’s still there if you know where to look.

As they put drew their graphs I went around the classroom, paying special attention to the students working on ionization energy and electronegativity. Especially for the latter, I’d picked pairs who I figured would be able to get the graphs done quickly but would appreciate the extra challenge of figuring out what electronegativity actually is. This way, when everyone was done, the students could use their graphs to look for the patterns and explain what they’d found to the rest of the class.

The patterns of electronegativity rises across the first twenty elements.

Citing this post: Urbano, L., 2013. Patterns in the Periodic Table, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

# Learning the Periodic Table: A Prototype

#### January 3, 2013

My middle school class is about to cover some very basic chemistry so I’ve asked them to memorize the first 20 elements in their correct order on the periodic table. To help, I’ve put together this interactive exercise where they drag an icon of the element to its correct place on the table. It says the name of the element whenever you start dragging a tile with the symbol. It’s also timed so students can quantify and compare how good they are.

In this first prototype the elements are presented in order, but I figure that additional levels could have:

• The elements come up at random (done).
• Have the elements come up by vertical column (group) (done).
• Instead of tiles with the elements, have diagrams with their electron configuration.
• The program say the name of the element and the student has to click on the right cell in the table.

This was put together using HTML5 and Javascript. KineticJS was particularly useful. It should, in theory, work in any browser (but I have only tested it in Firefox and Google Chrome) and on touch-screen tablets as well.

Citing this post: Urbano, L., 2013. Learning the Periodic Table: A Prototype, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

# Personal Ceramic Project

#### December 24, 2011

I have a neat little tea strainer that sits inside my almost perfect teacup, yet I’m usually at a loss about what to do with it when I take it out of the cup. When the lid is upside down, the strainer can sit nicely into a circular inset that seem perfectly designed for it; however, if I want to use the lid to keep my tea warm — as I am wont to do — I have to move the strainer somewhere else.

One option is to just put the strainer in another cup, but then air can’t circulate around it, and instead of drying, the used tea leaves stay wet and, eventually, turn moldy. A flat saucer would be better, but not perfect.

Of course, I could just empty out the strainer, wash and dry it as soon as I’m done steeping the leaves, but there are a few ancillary considerations with respect to time that make this a sub-optimal solution.

So, since we have a kiln on campus that sees regular use, I thought I’d sit in on the Middle School art class and make my own ceramic tea strainer holder. Since I’ve also been thinking about Philip Stewart’s spiral, and de Chancourtois‘ helictical periodic tables, and been inspired by Bert Geyer’s attempts at making sonnets tangible, it eventually occurred to me that an open helictical form would work fairly well for my purposes.

I’ve cobbled together a design using Inkscape, and layered it onto a cylinder in Sketchup to see what it would look like.

Draft model of a tea strainer holder.

So far the reactions from students has been quite diverse. I have one volunteer who’s wants to help, and I’ve sparked some discussion as to if what I’m doing actually qualifies as art. There is a lot of curiosity though. The middle-schoolers will probably be doing some type of physical representation of the periodic table, so I’m hoping this project gets them to think more broadly about what they might be able to do.

Citing this post: Urbano, L., 2011. Personal Ceramic Project, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

# The History of the Periodic Table

#### November 22, 2011

Fitted to a cylinder, the elements on this periodic table would form a spiral. Image via Wikipedia.

Spurred by Philip Stewart‘s comment that, “The first ever image of the periodic system was a helix, wound round a cylinder by a Frenchman, Chancourtois, in 1862,” I was looking up de Chancourtois and came across David Black’s Periodic Table Videos. They put things into a useful historical context as they explore how the patterns of periodicity were discovered, in fits and starts, until Mendeleev came up with his version, which is pretty much the basis of the one we know today.

The cylindrical version is pretty neat. I think I’ll suggest it as a possible small project if any of my students is looking for one. You can, however, find another interesting 3d periodic table (the Alexander Arrangement) online.

Citing this post: Urbano, L., 2011. The History of the Periodic Table, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

# Why Gold is Precious

#### November 20, 2011

The precious metals are those few that are not gasses, and not reactive. Of these, only gold (Au) and silver (Ag) are not extremely rare and hard to extract and work.

A while back, I posted a radio article by Planet Money on why gold is so valuable, and has been used for money for so long (God, Glory and GOLD: but why gold?). They’ve now created a nice video explaining the same thing. Though there’s less detail, the dramatic visuals (of the reactivity of sodium for example) make it quite interesting.

Citing this post: Urbano, L., 2011. Why Gold is Precious, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

# 3d Molecule of the Month

#### September 24, 2011

Cyclohexane, from the interactive model on 3Dchem.com.

Molecular models tend to fascinate. As a introduction to the chemistry of elements, students seem to like putting them together, and they tend to enjoy finding out what their molecules are called.

You can’t beat fitting together molecules by hand as a learning experience, but 3Dchem has a nice collection of interactive, three-dimensional molecules, including molecules of the month.

Periodic spiral of the elements (from 3Dchem.com).

They also have three-dimensional periodic tables showing the sizes of the atoms in the traditional tabular form as well as a spiral.

Periodic Table showing the elements by size.

Citing this post: Urbano, L., 2011. 3d Molecule of the Month, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.

# Periodic Table Spiral Galaxy

#### September 22, 2011

The objective is to show the shape of the whole and to express the beauty and cosmic reach of the periodic system.

— Stewart (2006): The Chemical Galaxy

Chemical Galaxy II: A new vision of the periodic system of the elements by Philip Stewart.

Periodic Table of the Elements - a traditional view by Wikimedia Commons User:Cepheus.

The traditional periodic table of the elements breaks the elements into rows as their chemical and physical characteristics repeat themselves. But since the sequence of elements is really a continuous series that gradually increases in mass, a better way of displaying them might be as the spiral, sort of like the galaxy.

When the chemical elements are arranged in order of their atomic number, they form a continuous sequence, in which certain chemical characteristics come back periodically in a regular way. This is usually shown by chopping the sequence up into sections and arranging them as a rectangular table. The alternative is to wind the sequence round in a spiral. Because the periodic repeats come at longer and longer intervals, increasing numbers of elements have to be fitted on to its coils. …

The resulting pattern resembles a galaxy, and the likeness is the basis of my design. It seems appropriate, as the chemical elements are what galaxies are made of.

The ‘spokes’ of the ‘galaxy’ link together elements with similar chemical characteristics. They are curved in order to keep the inner elements reasonably close together while making room for the extra elements in the outer turns.

— Stewart (2006): The Chemical Galaxy

While the spiral version of the periodic table is not used a lot, it is scientifically valid. There are other ways of representing the spiral and the periodic table itself. It all depends on what you want to show.

Benfey's spiral table first appeared in an article by Glenn Seaborg, 'Plutonium: The Ornery Element', Chemistry, June 1964, 37 (6), 12-17, on p. 14. (via Wikimedia Commons)

Indeed, Mendeleev’s monument in Bratislava, Slovakia has the elements arranged as the spokes in a wheel.

Monument to the periodic table and Dmitri Mendellev (photo by mmmdirt, caption via Wikipedia).

Citing this post: Urbano, L., 2011. Periodic Table Spiral Galaxy, Retrieved January 22nd, 2018, from Montessori Muddle: http://MontessoriMuddle.org/ .
Attribution (Curator's Code ): Via: Montessori Muddle; Hat tip: Montessori Muddle.