The Periodic Table Ch.5-Sec.1 (pp. 106-109)

Dmitri Mendeleev 1869

Mendeleev organized the table by Atomic mass This was later changed and organized by atomic number.

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Lets watch Bill to give us some background information concerning the periodic table of elements. Greatest Discoveries with Bill Nye: Chemistry

Describes something that occurs or repeating intervals p. 107 Periodic Describes something that occurs at regular or repeating intervals p. 107

The Periodic Table of Elements

Gaps in the Periodic Table Why were there gaps in the table? p. 107 All the elements were not as yet discovered. Mendeleev was able to predict there would be elements to fill the gaps. In later years, the gaps were filled as Mendeleev predicted.

1914 to modern day 30 + elements have been discovered since 1914 follow the periodic law Fun Fact: In the late 1800’s scientists experiments with burning elements. They found that each element, when heated produced its own color “spectra.”

Periodic Law p. 107 The repeating chemical properties of elements change periodically with the atomic numbers of the elements.

Atomic Number What property is used to arrange the periodic table? All elements fit the pattern when they were arranged by: Atomic Number

+ Concept Map or Atom Neutron Electron Proton Atomic Mass Atomic Number

Label the diagram 7 N Nitrogen 14.01 Atomic Number Element Symbol Element Name Atomic mass

7 Periods (rows) p. 108 P E R I O D S

Mini-quiz Period Group A row is known as a A column is known as a #14 and #15

18 Groups (families) Up & Down

Zigzag Line Reminds us where the metals, nonmetals, and metalloids are.

Mass numbers with parenthesis are radioactive elements’ most stable isotope

These names and symbols are temporary Three letter symbols These names and symbols are temporary Discovered in 1994, but not approved until 2004… Ten years is a long time to wait, but you still get to name the element if you discovered it. These elements have to be approved by an international committee of scientists.

The lifting agent for the ill fated Hindenburg balloon was hydrogen rather than the safer helium.