Simplest Matter Elements

Element- Matter made of only one kind of atom. –112 known elements (92 naturally occur on Earth) 20 synthetic elements (made by scientists)

Periodic Table Chart used to organize and display the elements International system understood by scientists everywhere.

Periodic Table Elements organized on periodic table by their properties –Rows are called periods Elements in a row have same number of energy levels –Columns are called groups Elements in a column have similar properties related to their structure also form similar bonds (Same Valence Electrons!!!!!!!)

Identifying Characteristics Each element is different and has unique properties Atomic Number- Tells you the number of protons in the nucleus of each atom of that element. Mass Number- Number of protons plus the number of neutrons it contains. Atomic Mass- Weighted average mass of the isotope of an element. Isotope- Atoms of the same element that have different number of neutrons.

Classification of Elements 3 general categories: Metals, nonmetals, and metalloids Metals- Generally have a shiny or metallic luster and are good conductors of heat and electricity –All solid at room temperature except mercury –Malleable (bent or pounded into various shapes) –Ductile (drawn into wires without breaking)

Classification of Elements Nonmetals- Usually appear dull in appearance and are poor conductors of heat and electricity. –Many are gasses at room temperature –97% of body is made up of various nonmetals

Classification of Elements Metalloid- Elements that have characteristics of metals and nonmetals –Solid at room temperature

Where Do Elements Come From? WtFtEMhttp:// WtFtEM