5 Elements

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5 Elements
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Elements

• Many atoms of the same type make up an element.
• Each element has characteristic chemical and
  physical properties, or traits, that give it a
  unique identity.

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• Elements are organized according to their
  properties in the periodic table of the elements.
• The properties of elements depend on the
  structure of its atoms.

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• The number of protons in the nucleus is
  especially important and equals the atomic
  number.
• The first periodic tables arranged elements by
  their atomic masses (protons and neutrons)

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• Scientists later realized that properties of
  elements varied by their atomic number not by
  their atomic mass
• The number of protons equals the number of
  electrons in an atom.

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• The number and arrangement of electrons in the
  outermost energy level determine the chemical
  behavior of an atom.
• On the periodic table, elements with the same
  number of electrons in their outer most energy
  level are arranged in a vertical column in the
  chart

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Chemical Families

• They are grouped in chemical families, such as
  the hydrogen family.
• All elements in the same family have the same
  electron arrangement in their outermost energy
  levels.

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