Download What is the periodic table of elements - Net Start Class

Enduring Understandings
As matter and energy cycle through systems, atoms and
molecules are transformed and recombined in different
ways.
Technical Reading
Dmitri Did It!
Concepts Important to Know and Understand
Energy stored and released through chemical bonds
EQ: How does a system maintain balance?
Broad Brush Knowledge
properties of matter
Targeted Skills

Communication
 Determine purpose
 gather information
 Analyze words
 identify context clues
Purpose
Core Objectives
4 Identify the structure and properties of atoms and elements.
5 Determine properties used to position an element within the
periodic table.
6. Identify the transformations of atoms, molecules, and energy
that occur within cycles in the environment.
Gather information and develop technical reading skills.
Expert Information: Dmitri Mendeleev was a Russian scientist who lived in the 1800’s. Only 60
elements were discovered during his lifetime. In 1869, Mendeleev organized the information
known about these elements and created a chart called the periodic table of the elements.
Since that time, fifty-six additional elements have been discovered and added to the chart.
Scientists all over the world use the same periodic table.
+
-
electrons
+
+
-
nucleus
3
protons
Li
neutrons
energy levels
Atomic structure of lithium
Lithium
6.941
Atomic number =
number of protons
Atomic mass =
number of protons +
neutrons
Periodic table entry for lithium
Compare the atomic structure of lithium to its position on the periodic table. Since an
atom of lithium has three protons, lithium’s atomic number is 3. Three neutrons plus three
protons in the nucleus results in lithium having an atomic mass of 6. Not all atoms of an element
are identical. Some lithium atoms have additional neutrons, which causes these atoms, called
isotopes, to have greater mass. Atomic mass is the average mass of all isotopes of an element.
Elements are arranged on the periodic table by their atomic numbers. Typically, atomic numbers
are in the same order as atomic masses.
The periodic table is a grid of rows and columns. The seven rows are called periods. Each
atom of an element in a period has the same number of energy levels. Lithium has two energy
levels, so it occurs in period two. Each of the 18 columns is a group, or family, of elements. All
of the elements in a group have many similar chemical properties. These similarities occur due to
the elements in a group having the same number of electrons in the outer energy level.
Elements are classified into two groups—metals and nonmetals. The stair-step line on
the periodic table separates metals on the left from nonmetals on the right. There are more
metals than nonmetals. Metals share certain physical properties such as the ability to conduct
heat and electricity. Metals can be formed into shapes. Nonmetals usually do not conduct
electricity and cannot be formed into shapes.
© 2006 Plano ISD, Plano, TX/Klein ISD 2007©
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Find each of these elements on the periodic table and fill in the missing information.
Period
Group
3
2
2
18
5
11
7
1
6
14
Element
Symbol
Atomic Number
1. What is the lightest element on the chart above? What is its atomic number?
2. What term refers to rows of elements?
3. What term refers to columns of elements?
4. Do groups or periods classify elements that have similar properties?
5. On the periodic table, where are metals listed?
6. On the periodic table, where are nonmetals listed?
7. Are there more metals or nonmetals?
8. How are elements listed on the periodic table?
Find each of these elements on the periodic table and fill in the missing information.
Period
Group
Element
Symbol
Atomic Number
osmium
beryllium
arsenic
zinc
nitrogen
9. Which of these elements are metals?
10. Which of these elements are nonmetals?
11. List two elements that have many similar properties.
12. Why do these two elements have many similar properties?
© 2006 Plano ISD, Plano, TX/Klein ISD 2007©
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