What is an element ?
An element is a pure substance that cannot be broken down into simpler chemicals. An element is made up of only one type of atom. So , the element hydrogen is made only of hydrogen atoms and gold of gold atoms.
Where do elements Come From ?
Most scientists believe that much of the hydrogen and some of the helium in the universe were formed “big bang” that formed the universe. Hydrogen has the smallest and simplest atoms and helium has the next smallest.
Some elements are made of atoms so large , they spontaneously break apart. This is called radioactive decay , and the subatomic particles ( smaller than atoms) and energy released by it can be dangerous. Each radioactive element has a half life , the time it takes for half of its atoms to break apart.
Group – Transition metals
Discovery date – Unknown (prehistoric times)
Melting point – 1064°C (1947°F)
Boiling point – 2856°C ( 5173°F)
Gold gets people excited. It has been prized and valued since prehistoric times , and turned into many crowns , idols , and crosses over the centuries. Gold never looses its shine and it easy to melt and mould. It is measured in carats – pure gold is 24carats .
Group – noble gases
Discovery date – 1868
Melting point – 272°C (-458°F)
Boiling point – 269°C (-452°F)
Helium is the second most abundant element in the universe , after hydrogen. It was discovered in space , before we found it on earth. It weighs very little and is used to make things float , such as airships and balloons it is also used in liquid form as a coolant in big scientific computers.
Group – transition metals
Discovery date – unknown (prehistoric times)
Melting point – 1538°C (2800°F)
Boiling point – 2862°C ( 5182°F)
Iron is a versatile and abundant metal. We use it to build bridges , make machines and cutlery. Iron is vital to your well-being it gives red blood cells their color , and helps to carry oxygen around your body. The center of earth is made of iron.
Group – Transition metals
Discovery date – pre 1500BCE
Melting point – 39°C ( -38°F)
Boiling point – 356°C ( 674°F)
Mercury is a poisonous , although in ancient times it was thought to have healing and life giving properties. Early chemists (alchemists) once thought it held the secret to making gold. At room temperature mercury is liquid.
Group – Actinides
Discovery date – 1789
Melting point – 1132°C (2070°F)
Boiling point – 4131°C ( 7468°F)
Uranium is naturally occurring radioactive metal and was named after the planet Uranus. It is refined and used in industry , nuclear power station , warfare. In the 1940s it was used to make atomic bomb “LITTLE BOY” that was dropped in Hiroshima in 1945.
Group – Non – metals
Discovery date – unknown ( prehistoric times)
Melting point – Diamonds 3852°C (6917°F) sublimes 4800°C (8672°F)
Carbon is vital to all living things and on the earth it is frequently exchanged between the air , living things , and the soil in never ending cycle. Carbon atoms can join together to make coal and diamonds , as well as with other elements to make more than 10 million compounds.
Group – Non metals
Discovery date – 1669 by German chemists Hennig brand .
Melting point – 44°C (111°F)
Boiling point – 277°C (531°F)
This fiery element is very reactive and so isn’t found naturally on the earth. Phosphorus is used to make matches , fertilizers and and some weapons. It is also a component of DNA , and helps to make energy in your body.
Group – Alkaline – earth metals
Discovery date – pre 100CE
Melting point – 842°C ( 1548°F)
Boiling point – 1484°C (2703°F)
Calcium is the most abundant metal found in living organisms and is vital for many cellular reactions . It is also a key components of bones and cells , giving them strength. Calcium is so found in milk , chalks , seaweeds.