**Part 1: Matching**

Place the letter for the correct element category from the list below next to each description.

**Part 2: Fill in the Blank**

Write the word or phrase that best completes each sentence. Choose from the following: group, period, atomic number, periodic, metal, metalloid, nonmetal, chlorine, magnesium.

1. The elements on the periodic table are arranged in order of increasing _____________________.
2. The arrangement of the elements on the periodic table shows a predictable, repeating ___________ pattern that allows us to predict chemical properties.
3. The elements Na, Mg, and Cu are each classified as ___________________ elements.
4. When elements are located in the same ______ they exhibit similar chemical and physical properties.
5. The element ________ is an example of an element that is classified as a nonmetal.

**Part 3: Classifying**

For each electron configuration, identify the element and decide which group the element belongs to on the periodic table. (Hint: Find the total number of electrons for each and refer to page 186 in your Student Book to determine the element and group number.)

| Electron Configuration | Element | Group Number |
|------------------------|---------|--------------|
| 1. 1s² 2s² 2p⁶ | | |
| 2. 1s² 2s² 2p⁶ 3s² | | |
| 3. 1s² 2s² 2p⁶ 3s² 3p⁶ | | |
| 4. 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² | | |
| 5. 1s² 2s² 2p⁶ 3s² 3p³ | | |

**A NATURAL APPROACH TO CHEMISTRY**

1. ___ The element sodium (Na) belongs to this group of elements.
2. ___ These elements are not likely to chemically bond with other elements.
3. ___ These elements are located in the center of the periodic table.
4. ___ These elements tend to gain one electron to fill their outer shell and are sometimes colored gases.
5. ___ These elements have two electrons in their highest unfilled energy level.