Dmitri Mendeleev Mid 1800s

1
Dmitri Mendeleev (Mid 1800s)

• Mendeleev arranged the elements into rows in
  order of increasing mass so that elements with
  similar properties were in the same column.
• Left spaces for undiscovered elements.

2
Periodic Table

• A periodic table is an arrangement of elements in
  columns, based on a set of properties that repeat
  from row to row.
• Periods are the rows in the periodic table that
  represent energy levels. Elements change from
  metals to nonmetals as you move from left to
  right across the period.
• Groups/Families are the columns on the periodic
  table. Properties of elements repeat in a
  predictable way. (Periodic Law)

3
Atomic Mass

• Atomic mass is a value that depends on the
  distribution of an elements isotopes in nature
  and the masses of those isotopes.
• An atomic mass unit is 1/12th the mass of a
  Carbon-12 atom.

4
Metals

• Metals are elements that are good conductors of
  electric current and heat. Also, they are
  malleable, ductile, have a high melting point and
  have a metallic luster.
• Metals tend to lose electrons and form positive
  ions.

5
Nonmetals

• Nonmetals are elements that are poor conductors
  of heat and electricity. Many have low melting
  points and are gasses at room temperature.
• Tend to gain electrons and form negative ions.

6
Metalloids

• Metalloids are elements with properties that fall
  between those of metals and nonmetals. A
  metalloids ability to conduct electric current
  varies with temperature.

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Valence Electrons

• A valence electron is an electron that is in the
  highest occupied energy level of an atom.
• Elements in a group have similar properties
  because they have the same number of valence
  electrons.

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Alkali Metals

• Group 1A
• Most reactive metals
• Reactivity increases from the top to the bottom.
• So reactive many are kept under oil to prevent
  reacting with water or oxygen.
• One Valence Elctron
• Found in nature only in a compound.
• Form 1 ions

9
Alkaline Earth Metals

• Group 2A
• 2 Valence Electrons
• Form 2 Ions
• Magnesium used in photosynthesis.
• Calcium used in teeth and bone.

10
Boron Family

• Group 3A
• 3 Valence electrons
• Form 3 Ions
• 1 metalloid (Boron)
• Five metals
• Aluminum is the most abundant metal in the
  Earths crust.

11
Carbon Family

• Group 4A
• 4 Valence Electrons
• Form /- 4 Ions
• 1 Nonmetal
• 2 Metalloids
• 3 Metals
• With the exception of water , most of the
  compounds in your body contain carbon.

12
Nitrogen Family

• Group 5A
• 5 Valence Electrons
• Forms -3 Ions
• 2 nonmetals
• 2 metalloids
• 2 Metals
• Nitrogen and Phosphorus are used in fertilizers.

13
Oxygen Family

• Group 6A
• 6 Valence Electrons
• Forms -2 Ions
• 3 nonmetals
• 2 metalloids
• 1 metal
• Oxygen is the most abundant element in the
  Earths Crust.

14
Halogens

• Group 7A
• 7 Valence electrons
• Form -1 Ions
• Most reactive nonmetals increase from bottom to
  top.
• Known as Salt Formers
• 5 nonmetals
• 1 Unknown

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Noble Gases

• Group 8A
• 8 Valence Electrons
• Un-reactive (Do not form Ions)
• The Noble Gases are odorless and colorless.
• Used in light bulbs.