MAGNUS CARLSEN

Here is our project about Magnus Carlsen:

( Click image to go to the presentation)

Vocabulary Units 5 & 7

Unit 5

Have a lie-in : Get up late
Feel worried : Preoccupied
Share a room: Use together a room
Have a sleepover: Sleep in a friend´s house

Unit7 

Sting: Ar insect or animal produce a bit injury
Bite: Ar insect or animal produce a bit injury with the mouth
Fightback: Return to fight

 

FLUORINE

Fluorine is a chemical element with symbol F and atomic number 9. It was discovered by Henri Moissan in 1886 ; the name is derived from the latin “ fluere “ , meaning to flow . The fluorine melting point is -219 º C and his boiling point -188 º C . Fluorine has 18 known isotopes from 14 to 31, only one of these isotopes is stable, that is, fluorine-19

Appearance and properties

A very pale yellow-green, dangerously reactive gas. It is the most reactive of all the elements and quickly attacks all metals.

Uses

There was no commercial production of fluorine until the Second World War, when the development of the atomic bomb, and other nuclear energy projects, made it necessary to produce large quantities. Before this, fluorine salts, known as fluorides, were for a long time used in welding and for frosting glass.

The element is used to make uranium hexafluoride, needed by the nuclear power industry .

Biological role

Fluoride is an essential ion for animals, strengthening teeth and bones. The average human body contains about 3 milligrams of fluoride. Too much fluoride is toxic. Elemental fluorine is highly toxic.