Periodic Table (of Elements)

• Periodic Table (of Elements:

  arrangement of elements based on atomic number

  (number of protons)
• Periodic Table (of Elements:

  3 main groups:

  metals (towards the left side)

  non-metals (towards the right)

  metalloids (between metals & non-metals)
• Groups:

  18 groups (families)
• Groups:

  elements in a group tend to have similar physical

  and chemical properties
• Groups:

  group 1- alkali metals: Li, Na, K, etc are shiny,

  silvery, form compounds that are mostly white

  solids, and are very soluble in water;
• Groups:

  group 2- alkaline earth metals: Mg, Ca, Ba, etc

  are shiny, silvery, but mostly insoluble in water;
• Groups:

  groups 3 to 12 are called transition metals;
• Groups:

  group 17- halogens: F, Cl, Br, etc poisonous and

  highly reactive with alkali metals
• Groups:

  group 18- noble gases: He, Ne, Ar, etc don’t

  form compounds;
• Atomic Structure:

  Arrangement of electrons about the nucleus and

  especially the electrons in the outer shell is the key to the

  understanding of chemical reactions, and the formation

  and naming of compounds along with their chemical

  formulas.
• Valence Electrons:

  Outer shell-valence shell
• Valence Electrons:

  Electrons in outer shell-valence electrons
• Valence Electrons:

  Valence shells have the most energy (of all the shells).
• Valence Electrons:

  Chemical properties of elements are related to the energy

  changes that take place when their atoms gain, lose, or share

  electrons to obtain a filled valence shell.

  (*A shell is considered filled if it has 8 electrons)
• Valence Electrons:

  The farther the valence electron is from the positive nucleus, the more easily it is removed, and the more reactive the atom is.
• IONS:

  If an atom gains, or loses, an electron it becomes

  an ION, a charged atom.
• LEWIS ELECTRON DOT DIAGRAMS:

  used to represent an atom and its valence electrons
• LEWIS ELECTRON DOT DIAGRAMS:

  place a dot (representing an electron) on any side of an

  imaginary square around the symbol for the element
• LEWIS ELECTRON DOT DIAGRAMS:

  for more than 4 valence electrons, arrange the dots in groups of

  two