Development of periodic table

• What should you be able to describe by the end of the video on the periodic table?

  Early attempts to arrange the elements into a periodic table
• Why is the periodic table called "periodic"?

  Because elements with similar properties occur at regular intervals
• What are the groups in the modern periodic table?

  Group one, group two, transition elements, groups three to seven, and group zero
• What types of elements are found in group one of the periodic table?

  Highly reactive metals such as lithium, sodium, and potassium
• What types of elements are found in group seven of the periodic table?

  Highly reactive nonmetals such as fluorine, chlorine, and bromine
• Why do elements in the same group have similar chemical properties?

  Because they have the same number of electrons in their outer energy level
• Who was the scientist that first noticed elements with similar properties occurred in threes?

  Johan Dober
• What did Johan Dober call the groups of three elements with similar properties?

  Triads
• What did John Newlands observe when he arranged elements by increasing atomic weight?

  Every eighth element reacted in a similar way
• What is the name of Newlands' principle regarding the arrangement of elements?

  Law of octaves
• What should you be able to describe by the end of the video on the periodic table?

  Early attempts to arrange the elements into a periodic table
• How did Dmitri Mendeleev's periodic table predict the properties of elements?

  By arranging elements in order of increasing atomic weight and leaving gaps for undiscovered elements
• What is the structure of the modern periodic table?

  It is arranged into columns called groups
• What was a major problem with Newlands' law of octaves?

  Elements were sometimes grouped together with totally different properties
• Who developed the first modern periodic table?

  Dmitri Mendeleev
• How did Mendeleev arrange the elements in his periodic table?

  In order of increasing atomic weight
• What does the term "periodic" mean in the context of the periodic table?

  It means occurring at regular intervals
• What unique approach did Mendeleev take when arranging elements?

  He switched the order of specific elements to fit patterns
• Which group consists of highly reactive metals?

  Group one
• What did Mendeleev do when he encountered undiscovered elements?

  He left gaps in his periodic table for them
• Which group consists of highly reactive nonmetals?

  Group seven
• Why do elements in the same group have similar chemical properties?

  Because they have the same number of electrons in their outer energy level
• What did Mendeleev predict about the undiscovered elements?

  He predicted their properties based on other elements in the same groups
• What was the main difference between Mendeleev's table and the modern periodic table?

  The modern table is arranged by atomic number instead of atomic weight
• Why is ordering by atomic weight problematic?

  Elements can appear in the wrong order due to isotopes
• What is an example of elements that are incorrectly ordered by atomic weight?

  Thorium and iodine
• What does the modern periodic table include that Mendeleev's did not?

  Group zero, the noble gases
• What did Döbereiner call the groups of three elements with similar properties?

  Triads
• What was John Newlands' observation about the elements when arranged by atomic weight?

  Every eighth element reacted in a similar way
• What did Newlands call his principle regarding the arrangement of elements?

  Law of octaves
• What was a major problem with Newlands' law of octaves?

  Elements were sometimes grouped together with totally different properties
• What did Dmitri Mendeleev do differently when arranging the periodic table?

  He switched the order of specific elements to fit patterns
• How did Mendeleev handle undiscovered elements in his periodic table?

  He left gaps for them
• What was the significance of Mendeleev predicting the properties of undiscovered elements?

  It led to the acceptance of his periodic table by other scientists
• How is the modern periodic table different from Mendeleev's table?

  It is arranged by atomic number instead of atomic weight
• What is the atomic number?

  The number of protons in an element
• Why is ordering by atomic weight problematic?

  Elements can appear in the wrong order due to isotopes
• Which two elements are mentioned as examples of problems with ordering by atomic weight?

  Thorium and iodine
• What additional group does the modern periodic table have that Mendeleev's did not?

  Group zero, the noble gases
• What should students expect to find plenty of questions on in their vision workbook?

  The topic of the periodic table