Transcript How are elements organized

Chapter Four
How are elements organized?
 Pure elements at room temperature and
atmospheric pressure can be solids liquids or
gases
 Periodic law- states that the repeating
physical and chemical properties of elements
change periodically with their atomic number
 A horizontal row is called a period and a
vertical row is called a group
Periodic table
 Elements in groups 1,2 and 13-18 are known
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as the main- group elements
Group 1 is called alkali metals
Group 17 is the halogens
Group 18 is the noble gasses
( look at p.126-130 for more info.)
A solid or liquid mixture of two or more
metals is an alloy
Things to remember
 Ionization energy: the energy required to
remove an electron from an atom or ion
 Bond radius: half the distance from center to
center of two like atoms that are bonded
together
 Electro-negativity: a measure of the ability of
an atom in a chemical compound to attract
electrons
Types of elements
 Natural elements: most atoms of living things
come from these 6 elements carbon, hydrogen,
oxygen, nitrogen, phosphorus, and sulfur
 Synthetic elements: elements that chemists have
synthesized that do not occur naturally
 Super heavy elements: an element whose atomic
number is greater than 106