periodictablewashers

Periodic Table

Assemble a periodic table with different colored washers

Material

20 washers, 10 one color 10 a different color, we use steel 1/4 inch washers.
a flat refrigerator magnet
a piece of paper or cardboard

Assembly

Place the magnet underneath the cardboard or paper.

To Do and Notice

First activity

Let the protons be the lighter color washers and the neutrons the darker color.

Place one proton, light colored washer onto the paper covered magnet.

This models the element hydrogen's most common isotope. Atomic number 1, atomic mass approximately 1.

Add a neutron, dark colored washer.

This models the deuterium isotope of hydrogen. With chemical symbol D, making "heavy water" D2O. Atomic number 1, atomic mass approximately 2,

Add another neutron making tritium, T, a radioactive isotope of hydrogen used in nuclear fusion bombs. Atomic number 1, atomic mass approximately 3.

Second Activity

Now place two protons on the magnet plus two neutrons.

This models a helium nucleus with atomic number 2 and atomic mass approximately 4.

A helium nucleus is also known as an alpha particle.

Two particles with the same number of neutrons are known as isotones. In the different nuclei we have made so far which are isotones?

Remove one neutron from the helium to make "helium 3"

Compare helium 3 to Tritium.

Third Activity

Make another element, give it to your neighbor to figure out which element you have made.

So What?

In a neutral atom the number of electrons must equal the number of protons.

Since every charge cluster is surrounded by an inverse square force field, this sets up the fundamental shapes of the allowed orbitals for the electrons. The most basic shape is the sphere, given the symbol s, the next shape is a dumbbell, with symbol p, the next is a dumbbell with a donut around its middle, symbol d, and the next is a dumbbell with two donuts, symbol f.

These orbitals exist for each charged nucleus. As electrons are added they fill up the orbitals. Thus hydrogen has one electron in the s orbital.

The chemical properties of the elements are determined by their arrangement of electrons.