What is the atomic number of chromium?

VOCAB LAB

Write down what you think each word means: electron, proton, neutron, orbital, valence electrons, element, metalloid, isotope, octet rule, and ion. Discuss your definitions with friends using reallife examples. Did you all come up with the same definitions? Turn to the text and the glossary if you need help.

The periodic table has several pieces of information about the atoms of the elements. In this activity, you will use the periodic table to investigate different elements.

Using a periodic table, answer the following questions. 1. What element has eight protons? 2. What is the atomic mass of magnesium? 3. How many electrons does an aluminum atom have? 4. What is the chemical symbol for silver? 5. How many elements are metalloids? How many are nonmetals? 6. What is the atomic number of iron? 7. How many protons, neutrons, and electrons does one atom of calcium have? 8. What is the atomic number of chromium? 9. Which element has an atomic mass of 65.38? 10. How many protons, neutrons, and electrons does the element sodium have?

To investigate more, select a few elements on the periodic table to research. How are they alike and how are they different? How does the periodic table give you information about the physical and chemical properties of these elements?

Check your answers in the resources at the end of this book.