The Periodic Table Chemistry

Do Now – 10/24/2011 How are elements arranged on the periodic table?

Review Electron Configuration There are 7 energy levels and corresponding sublevels. Electrons are arranged in specific ways on energy sublevels. Sublevels = s,p,d,and f.

Periodic Table Brown = S block Red = P block Yellow = D block Blue = F block

Practice Ne = 10 electrons 1s2 2s2 2p6 P = 15 electrons 1s2 2s2 2p6 3s2 3p3 [Ne]10 3s2 3p3 Ti = 22 electrons 1s2 2s2 2p6 3s2 3p6 4s2 3d2 [Ar]18 4s2 3d2 Ni = 28 electrons 1s2 2s2 2p6 3s2 3p6 4s2 3d8 [Ar]18 4s2 3d8

The Periodic Table Originally created by Demitri Mendeleev we will cover that tomorrow. The periodic table is organized into a grid with groups and periods. Each element is represented by an element box containing the element’s name, symbol, atomic mass, & atomic number.

Periods Rows = periods (b/c trends in properties repeat – they’re “periodic” – as you go across the rows)

What’s a periodic trend? Here’s an everyday example:

Groups/Families Columns = families or groups (b/c they have similar characteristics)

Horizontal rows are called PERIODS Periodic table Mendeleev The periodic table arranges all the elements in groups according to their properties. Vertical columns are called GROUPS Horizontal rows are called PERIODS

Learning Check 1 Which element is in group 1, period 4? A) Be B) Ca D) C

Learning Check 2 Which element is in group 14, period 3? A) Ge B) Na C) C D) Si

Parts of the Periodic Table The periodic table is divided into several sections. The three main divisions are: Metals Metalloids Non-metals Within those sections we divide it even further.

Metals

Metals On the left (EXCEPT H!) Metallic properties: Dense solids Shiny luster High melting points Tend to form positive ions Good conductors of electricity Malleable (can stretch into wire) Ductile (can beat into sheets)

Nonmetals

Nonmetals On the right (AND hydrogen!) Properties: Low melting points Low densities Dull luster Poor conductors of heat and electricity Many are gasses at room temperature If you forget which side is which, remember – Oxygen is NOT a metal.

Semi-metals or Metalloids

Metalloids Touching the stair step (except Al) To draw stair step: start between B and Al. Properties of both metals and nonmetals Good semiconductors

Chemical Families Group 1 (except H!): Alkali metals Explode in water Soft Group 2: Alkaline Earth metals Very reactive (Less reactive than alkali) Hard (why they’re called “Earth” metals) Groups 3 -12: Transition metals Group 17: Halogens Very reactive Group 18: Noble gasses Inert (don’t react)

Alkali Metals – Group 1A Soft metals, cut it with knife Highly reactive Good conductors of heat and electricity

Alkaline Earth Metals – Group 2A Shiny solids, harder than Alkali metals Less reactive than Alkali Metals React with oxygen Doesn't dissolve easily in water

Halogens – Group 7A Very reactive nonmetals Always found combined with other elements in nature

Transition metals Good Electrical Conductors The greater the hardness of the metal the higher the melting points Lustrous Malleable

Inner Transition Metals Divided into Lanthanides (top) & Actinide (bottom) Lanthanides – silvery, high melting pts Actinides - radioactive elements Only three actinides exist in nature

Noble Gases – Group 8A Last natural elements to be discovered Colorless Unreactive Very Stable