Ions

1
Ions

• Some elements achieve stable electron
  configuration through the transfer of electrons
  between atoms.
• When the highest occupied energy level of an atom
  is filled with electrons, the atom is stable and
  not likely to react.
• Cation (ion) Element loses electrons
• Anion (-ion) Element gaines electrons

2
Lewis Dot Diagram

• Diagram represents the elements symbol and the
  number of valence electrons the element
  possesses.
• Bonding Lewis Dot Structures Practice

3
Chemical Bonding

• A chemical bond is the force that holds atoms or
  ions together as a unit.
• Ionic bond is the force that holds cations and
  anions together. An ionic bond forms when
  electrons are transferred from one atom to
  another.
• Covalent bond is a chemical bond in which two
  atoms share a pair of valence electrons.

4
Ionization Energy

• The amount of energy necessary for an electron to
  overcome the attraction of the protons in the
  nucleus.
• Less Ionization Energy the easier it is for an
  electron to be removed.

5
Electron Affinity

• Electron affinity - the tendency of an atom to
  attract electrons. This characteristic determines
  the type of bond formed between atoms.
• Metals generally have a low electron affinity.
• Nonmetals generally have a high electron affinity

6
Properties of Ionic Compounds

• Crystals are solids whose particles are arranged
  in a lattice structure.
• The properties of an ionic compound can be
  explained by the strong attractions among the
  ions within a crystal lattice.
• When an ionic crystal is struck, ions are moved
  from there fixed position and ions with the same
  charge repel each other and the crystal shatters.

7
Chemical Formulas

• A chemical formula is a notation that shows what
  elements a compound contains and the ratio of the
  atoms or ions of these elements in the compound.
• Barium Ba2             Fluoride F-
• Calcium Ca2       Nitrate NO3-

BaF2
Ca(NO3)2
8
Sharing Electrons

• In a Covalent Bond atoms share electrons.
• Share 1 pair single bond
• Share 2 pair double bond
• Share 3 pair triple bond
• A molecule is a neutral group of atoms that are
  joined together by one or more covalent bonds.
• The attraction between the shared electrons and
  the protons in each nucleus hold the atom
  together in a covalent bond.

9
Diatomic Molecules

• When found in nature a pure elements, these seven
  elements exist only as two atoms covalently
  bonded.
• H2
• N2
• O2
• F2
• Cl2
• Br2
• I2

10
Polar Covalent Bonds

• A Polar Bond is when the electrons are not shared
  equally. (Attraction between particles is
  greater.)
• The atom with the greater attraction for
  electrons has a partial negative charge. The
  other atom has a partial positive charge.
• Symbol
• ?- negative
• ? positive
• The type of the molecule and the shape are
  factors that determine whether a molecule is
  polar or nonpolar.

11
Polyatomic Ions

• A polyatomic ion covalently bonded group of atoms
  that has a positive or negative charge and acts
  as a unit.

12
Naming Molecular Compounds

• The general rule is that the most metallic
  element appears first in the name.
• The name of the second element is changed to end
  in the suffix ide.
• Prefix is attached to represent the number of
  atoms.

13
Metallic Bonds

• The cations in a metal form a lattice that is
  held in place by strong metallic bonds between
  the cations and the surrounding valence
  electrons.
• Swimming in electrons.
• Allows metals to be
• Good conductors of electricity
• Malleable
• Ductile

14
Alloys

• An alloy is a mixture of elements and at least
  one is a metal. Alloys have properties of
  metals.
• Scientists can design alloys with specific
  properties by varying the types and amounts of
  elements in the alloy.

• Bronze copper and tin
• Steel Iron and carbon
• Airplanes Aluminum and copper or manganese.