1. Elements and their Symbols TEKS (5) Matter and energy. The student knows the differences between elements and compounds. The student is expected to: (A) know that an element is a pure substance represented by chemical symbols

2. All matter is made of atoms. Think of all the substances you see and touch every day. Are all of these substances the same? Obviously, the substances that make up the wall are quite different from the substances in the air around you. So how many different substances can there be? This is a question people have been asking for thousands of years. • How many different substances do you think there are? These substances are called elements.

3. All matter is made of atoms. • About 2400 years ago, Greek philosophers proposed that everything on Earth was made of only four basic substances—air, water, fire, and earth. Everything else contained a mixture of these four substances. • As time went on, chemists came to realize that there had to be more than four basic substances. Today chemists know that about 100 basic substances, or elements, account for everything we see and touch. Sometimes these elements appear by themselves. Most often, however, these elements appear in combination with other elements to make new substances.

4. Periodic Table of Elements • Scientists have worked to organize all the known elements of the universe into a specialized chart called the Periodic Table of Elements. Using chemical symbols to represent each element, the chart is used by scientists around the world. It makes no difference what country you are in or what language is spoken there. The language of chemistry is the same all over the world.

5. NAMES OF ELEMENTS • Elements get their names in many different ways. Magnesium, for example, was named for the region in Greece known as Magnesia. Lithium comes from the Greek word lithos, which means “stone.” Neptunium was named after the planet Neptune. The elements einsteinium and fermium were named after scientists Albert Einstein and Enrico Fermi. • Each element has its own unique symbol.

6. SYMBOLS OF ELEMENTS • For some elements, the symbol is simply the first letter of its name. • hydrogen (H) sulfur (S) carbon (C) • The symbols for other elements use the first letter plus one other letter of the element’s name. Notice that the first letter is capitalized but the second letter is not. • aluminum (Al) platinum (Pt) cadmium (Cd) zinc (Zn) • The origins of some symbols, however, are less obvious. The symbol for gold (Au), for example, doesn’t seem to have anything to do with the element’s name. The symbol refers instead to gold’s name in Latin, aurum. Lead (Pb), iron (Fe), and copper (Cu) are a few other elements whose symbols come from Latin names.

7. Please answer these questions in your journal. • About how many different elements make up everything on Earth? • How do elements get their names? • What is the chart that organizes elements called? • Please draw and complete the tables below in your journal.