Organizing the Elements

Mendeleev is known for discovering what?

• The periodic table

• The structure of DNA

• The theory of relativity

• The electron

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The periodic table contains information about:

• chemical elements and their properties

• historical events

• geographical locations

• mathematical formulas

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The periodic table is useful because it:

• organizes elements by increasing atomic number and similar properties.

• provides a list of all known compounds.

• shows the history of element discovery.

• predicts the weather patterns.

Compare and contrast Mendeleev’s periodic table with the modern periodic table.

• Mendeleev's table was based on atomic mass, modern table is based on atomic number.

• Mendeleev's table included noble gases, modern table does not.

• Mendeleev's table was arranged by atomic number, modern table is arranged by atomic mass.

• Mendeleev's table had no gaps, modern table has gaps for undiscovered elements.

The diagram shows an Element from the periodic table. Label the four facts shown about each element.

​ (a)   ​ (b)   ​ (c)   ​ (d)  

• Valence Electrons
• Group Number
• Atomic Number
• Element Symbol
• Element's name
• Atomic Mass
• Period Number

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In what order did Mendeleev arrange the elements in the periodic table?

• By atomic number

• By atomic mass

• Alphabetically

• By density

What do elements in the same column in the periodic table have in common?

• They have the same atomic number.

• They have similar chemical properties.

• They have the same number of electron shells.

• They have the same atomic mass.

What can you predict about an element from its position in the periodic table?

• Its atomic number

• Its chemical properties

• Its atomic mass

• All of the above

An element’s _______________ is its row in the periodic table.

• period

• group

• atomic number

• symbol

The __________________________ of an element is the average mass of all isotopes of that element.

• atomic mass

• atomic number

• electron configuration

• valence electrons