ELEMENTS OF COMPOUNDS

• ELEMENTS

  • The basic building blocks of Matter
  • An element is a substance that cannot be separated into simpler substances by chemical mean.
• • 118 elements have been positively identified. 94 of these occur naturally on earth. 24 are man-made.
• • Substances can be either elements or compounds
• • The entire universe is almost filled completely with hydrogen.
• • Here on earth, the common element is oxygen.
• • Eight of the 94 naturally occurring elements make up the outermost layer of the earth or the earth's crust.

  A) Oxygen

  B) silicon

  C) Aluminium

  D) Iron

  E) Magnesium

  F) Calcium

  G) Potassium

  H) Sodium

  
• • The Greek philosophers thousands years ago believed that all matter was composed of four elements: The earth, fire, air, and water.
• Elements are further classified as: Metals, Non-metals, and Metalloids.

   
• Metals have shiny surfaces, good conductors of heat and electricity, malleable (can be hammered into sheets), ductile (can be drawn out into wires). Examples include iron, copper, gold, silver, aluminum, lead, zinc, etc.
• Non-metals do not have shiny surfaces, poor conductors of heat and electricity, brittle (cannot be hammered into sheets), non-ductile (cannot be drawn out into wires). Examples include carbon, sulfur, nitrogen, chlorine, iodine, bromine, fluorine, etc.
• METALLOIDS

   

  • It behaves like metals and non-metals.
  • They have the same physical appearance as metals. They behave chemically like non-metals.
• Examples of metalloids include boron, arsenic, antimony, selenium, tellurium, polonium, and astatine.