STAAR Review – Day 2
Periodic Table
Formulas
1st developed by Dmitri Mendeleev
Periodic Table
Reading the boxes on the
Periodic Table
Atomic Number
(number of protons)
Element Symbol
Atomic Mass
Number (= P + N)
Element Name
Periodic Table
Metals
Transition Metals
Metals vs Nonmetals
Metals
Nonmetals
• Are good conductors of heat
and electricity
• Shiny
• Malleable
• Ductile
• Usually a solid at room
temperature (exception:
Mercury)
• Not good conductors of
heat and electricity
• Dull
• Not malleable
• Not ductile
• Usually a liquid or gas but
can be a solid at room
temperature
Reactivity
• Elements react to each other to create
molecules or compounds by bonding.
Bonding takes place at the electrons outer
energy level – the valence electrons.
• The Groups number helps you to understand
how many valence electrons are present in
groups 1, 2, and 13- 18. Group 18 does not
bond with other elements because the outer
energy level is complete.
Formulas
• Def. It is a written expression of an element or
compound.
• They are often written with a subscript.
(Example: O2 or H2O Water) When written like
this the small number describes the number of
atoms of the element right in front of it. The
example for water – the number 2 belongs to the
Hydrogen.
Chemical Formulas in Equations