113

Yumminium

Ym

Mass number ?

Objective: To get students to think about the periodic table and that new elements are being discovered all the time. Students will be asked to calculate the atomic mass and number of neutrons of Yumminium.

Materials:

Candy bars or cookies, which are made from the same recipe, of three different but uniform sizes.

I like to use Snickers Bars, fun size, regular, and king. Provide enough to share after the lesson.

1 Box

1 Towel

Gloves

Goggles

Tongs

Kitchen Scale (a large dial helps)

Premise:

Announce that a new element was discovered yesterday. The atomic number is 113 and the atomic symbol is Ym for Yumminium. It is extremely unstable and that once it exposed, it will not last long at room temperature. Ask the students where they think the name comes from. Explain how you acquired a sample of Yumminium to work with. Put on goggles and gloves.

Use a pair of tongs to remove the smallest type of Yumminium from a towel-draped box and place it in a kitchen scale.

Have a student read the mass (kg) from the scale and write it on the board. Do the same for the other two sizes.

Explain that each of the three types are isotopes of the element Yumminium. Each isotope has a different number of neutrons. Since the mass number is the combined mass of the protons and neutrons, the different number of neutrons accounts for the differences in mass. The different mass numbers are recorded to the right of the symbol for each isotope. Ask the students to calculate the number of neutrons for each isotope by subtracting the atomic number (the number of protons) from the mass of each isotope.

Have the students calculate the mass number from the average of the masses. The mass number is the average of these masses. Write that number on the board.

Finally, have the students calculate the number of neutrons for each isotope and for the element. Write those numbers on the board as well. Each student now receives a sample of Yumminium.

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Al Pajak

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