Activity 2

Activity 2: Atom and Atomic Structure

Lithium 3D Model

Neon 3D Model

Magnesium 3D Model

1. What is the atomic number for each of your models?

Lithium:  3
Neon:  10
Magnesium:  12

2. What is the atomic mass number for each of your models?

Lithium: 6.941
Neon:  20.1797

Magnesium:  24.305

3. In your models, which two subatomic particles are equal in number?

Protons and Electrons

4. How would you make an isotope for one of your models?  What would change with the model?

Lithium-4 contains three protons and one neutron. This is the shortest-lived known isotope of lithium. It decays by proton emission to helium-3 with half-life of about 10^-23 seconds. Lithium-4 can be formed as an intermediate in some nuclear fusion reactions.

5. Considering the overall volume of your element models, what makes up most of the volume of an atom?

The empty space

6. For one of your models, show with another image what happens when energy excites an electron.

Lithium excited

7. Once the electron is excited, what do we typically observe when the electron returns to the ground-state?

They are discharged.  Electrical charge is lost and they return to neutral again.  The electrons flow from the object to the ground. 

8. Why are some elements different colors when they are excited? Hint: when electrons are excited (by something like heat from an explosive) they move up to another orbital and when they fall back they release the energy in the form of light.

 The color depends on the amount of energy that is released.  This comes from the different quantities of electrons losing their energy in the different elements. 

9. With the Fourth of July coming up quickly, explain how the colors of fireworks arise.

The amount of energy that is released varies from all elements.  The energy can be characterized by the wavelength of light

Strontium or carbonate salts have the longest wavelength and come  with lower energy to produce a red flame

Copper oxychloride has a shorter wavelength and higher energy to produce a blue flame

Barium nitrate produces a green flame

Sodium salts produce a yellow flame

Charcoal or carbon makes for a orange flame



10.  Explain the overall organizational structure of the periodic table.

In the modern periodic table, the elements are placed progressively in each period from left to right in the sequence of their atomic numbers, with a new row started after a noble gas. The first element in the next row is always an alkali metal with an atomic number one greater than that of the noble gas.

A group or family is a vertical column in the periodic table. Groups are considered the most important method of classifying the elements. In some groups, the elements have very similar properties and exhibit a clear trend in properties down the group. Under the international naming system, the groups are numbered numerically from 1 to 18 from the leftmost column (the alkali metals) to the rightmost column (the noble gases)

Elements in the same period show trends in atomic radius, ionization energy, electron affinity, and electronegativity. Moving left to right across a period, atomic radius usually decreases. This occurs because each successive element has an added proton and electron which causes the electron to be drawn closer to the nucleus.

Because of the importance of the outermost electron shell, the different regions of the periodic table are sometimes referred to as periodic table blocks, named according to the subshell in which the "last" electron resides

Periodic Table. Wikipedia.  8 July 2012. Web.  8 July 2012. 

11. List two example elements for each of these groups or classes:

Alkali Metals: Lithium and Sodium
Alkaline Earth: Calcium and Barium
Halogens: Fluorine and Chlorine
Noble Gases: Helium and Neon
Transition Metals: Silver and Gold
Non-Metals: Boron and Carbon
Metalloids:  Silicon and Arsenic