Modern Periodic Table

What’s in the box?  What does the 1 stand for?  Atomic Number  This tells us what about an atom of H?  # of protons  What does the stand for?  Atomic Mass  This tells us what about an atom of H?  Mass in nucleus (# of protons and neutrons)

 On the modern periodic table, how are elements arranged?  In order of increasing atomic number, left to right  What do we call the columns (up and down) on the periodic table?  GROUPS (or families)  What do we call the rows (left and right) on the periodic table?  PERIODS

 What does periodic mean?  Having or being marked by repeated cycles  What element does period 1 begin with? HHHH  How many periods are there on the table? 7777 Periods

Groups  Two different number systems for groups  In the first numbering system, groups are number 1-8 and each number is followed by either an A or B  The groups labeled A are the main groups (1A thru 8A)  Representative elements  This is because they possess a wide range of chemical and physical properties  The groups designated with a B (1B thru 8B) are found in the center  Transition Elements  A more recent numbering system has been devised numbering 1-18

Classification of Elements  What was another pattern of organization you noticed on the periodic table?  Physical properties and states  3 main classifications of elements  Metals  Nonmetals  Metalloids

1. Metals  Elements that are shiny, smooth and clean  Solid at room temperature  Good conductors of heat and electricity  Malleable  Hammered flat into a sheet  Ductile  Drawn out into a wire

1. Metals  All group B and most group A elements  Staircase line is divider between metals and nonmetals (Boron 3A and Astatine 7A)  ALMOST all elements on left side of table are metals  What is the exception?  Hydrogen

Alkali and Alkaline Earth metals (Group A)  What does alkali mean?  basic  Alkali metals  Group 1A (except hydrogen)  Alkaline earth metals  Group 2A  Both alkali and alkaline earth metals are chemically reactive  Alkali metals more reactive…why do you think?  Valence electrons…how many do group 1A elements have?  Is this stable?

Transition Elements (Group B)  2 categories  Transition metals  Inner Transition Metals (2 types)

Inner Transition Metals  Located along the bottom of the periodic table  2 sets  Lanthanide series  Top row of the inner transition elements  These elements are used as phosphors  Substances that emit light when struck by electrons  Where have we seen this before?  Where do we see this today?  Actinide series  Bottom row of the inner transition elements

Transition elements  All other group B elements that are not inner transition elements  Basically the Group B elements we see on the actual periodic table…  Think of it as the ‘continental US’

3 main classifications of elements MetalsNonmetalsMetalloids

2. Nonmetals  Occupy the upper right side of the periodic table  Usually gases  Brittle, dull-looking solids  Poor conductors of heat and electricity  Bromine (Br) is the only nonmetal that is liquid at room temperature

Important nonmetals  Group 7A  Halogens  Highly reactive elements  What does this mean?  Why are they highly reactive?  Look at the valence electrons  Group 8A  Noble gases  Highly unreactive  Why?  8 valence electrons

3 main classifications of elements MetalsNonmetalsMetalloids

3. Metalloids  Border the stair-case line  Elements with physical and chemical properties of both metals and non-metals  Silicon and germanium  Two of the most important metalloids  Anyone know why?  Used in computer chips and solar cells

Everyday Examples  Metals?  Jewelry  Pot and pans  Cars  Nonmetals?  Air we breath  Nitrogen  Neon signs  diamonds  Metalloids?  Computer chips