The Elements On Our Earth

Elements in the Atmosphere Our atmosphere contains many elements that we need in order to survive… Nitrogen (N) gas in the atmosphere consists of N2 molecules (it is a diatomic molecule). Oxygen (O) is found as O2 molecules. Argon is found as a single, uncombined Ar atom. Carbon Dioxide is released by us into the atmosphere as CO2. 2

Elements on the Earth Our hydrosphere consists of all the water that occurs at the earth’s surface. The chemical formula for water is H2O. 3

Elements in the earth’s Crust The earth’s crust contains many elements such as Oxygen (O2), Silicon (Si), Aluminum (Al), Iron (Fe) and others! Oxygen is the most abundant element. It is also very reactive. Oxygen reacts with other elements for form solid mineral compounds (ie. sand)

Reactivity How strongly an elements reacts with other elements is an important chemical property called reactivity

Other elements Metals All metals have certain properties in common Metals conduct electricity and heat Malleable and ductile Solid state at room temperature (except mercury) Shiny in appearance Ex. Tin, Aluminium, Iron

Non Metals Have very different properties than metals Can be gases or solids (only 1 liquid – bromine) at room temperature Not shiny Poor conductors of heat and electricity Brittle, Non-ductile Ex. Hydrogen, Carbon, Sulfur

Metalloids Have properties of both metals and non-metals Solids at room temperature Can be shiny or dull May or may not conduct electricity Poor conductors of heat Brittle and non-ductile Ex. Silicon, Boron, Arsenic

Extraction of Metals Most metals are reactive and have to be contained in other compounds. These metals are mostly found in minerals A mineral is a solid pure substance that occurs naturally in the earth’s crust Mineral deposits are found in ores in the earth’s crust The minerals have to be extracted from the earth

Extraction of Metals When the ore is collected, the mineral goes through a process of concentration (to collect as much mineral as possible) Once in mineral form, a process called decomposition allows the metal to be extracted and the excess unwanted materials are discarded