Lesson 7 October 5th, 2010 The Elements

The Elements Elements are pure substances that consist of atoms. The periodic table consists of over 100 elements all of which have a certain spot on the table.

Metals Found on the Left side of the periodic table The majority of elements on the periodic table are metals. All metals, except for mercury are solids at room temperature. Metals have the following properties. Malleable: The ability to be hammered or bent into a shape.

Metals Lustre: They are shiny in appearance. Ductile: They can be pulled into a wire. Conductor of electricity: Electricity can travel through the metal.

Metals A mixture of two or more metals is called an alloy. The process of alloying different metals together can enhance the properties of the metal.

Metals Example: Pure gold Jewellery is too soft and easily damaged. By mixing it with other metals in small quantities it becomes much more useful as it is much stronger.

Metals can range from being very reactive to un-reactive, Gold us used for jewellery because it is so un-reactive, Sodium or Potassium on the other hand will reactive violently with water

Non-Metals Found on the Right side of the periodic table Most of the remaining elements in the periodic table are non-metals (17 of them).

Non-Metals Non-metals generally have these properties: Non-conductor of electricity in its solid form At room temperature most are gasses (11) or solids (5) and only one is liquid. Solids are brittle and lack the lustre of metals

Metalloids Found in the middle-right of the periodic table Some elements do not fit as metals or non- metals. These fit on either side of the staircase that divides the metals and the non- metals. They have some properties of metals and some properties of non-metals. They are called semiconductors because they do not conduct electricity well.

Metalloids It is easier to control the flow of electricity through semiconductors than it is conductors, which explains their wide use in electronics.

Metalloids Silicon is the most common metalloid, in its pure form it is shiny, grey and very brittle. Around 40% of all rock is silicon.

Element Symbols

Element Symbols Each language has its own name for each of the elements To help with communication, chemists worldwide have agreed to use the same set of symbols for the elements. The symbols are all taken from the Roman alphabet, which is the same alphabet used for English.

Element Symbols Some elements start with the same letter so in some cases the Latin name is used to obtain the letters for the symbol. For example, the elements silicon and silver, like sulphur, begin with the letter “s.” In fact, they both begin with “si.” To tell them apart, silicon was given the symbol Si. Silver, which has the Latin name argentum, was given the symbol Ag. An element symbol consists of one or two letters.

Element Symbols The first letter is always capitalized. If there is a second letter, it is not capitalized. For example, the symbol Co stands for the metal element cobalt, while CO represents a poisonous compound made up of carbon (C) and oxygen (O) produced in car exhaust.

How Element Symbols got their names English Name Symbol Non-English Name and Meaning Non-metals Hydrogen H Hydro genes –water generating Helium He Helios – the sun Neon Ne Neos – new Argon Ar Argos – inactive or idle Fluorine F Fluere – Flowing Chlorine Cl Chloros – Yellow-green

How Element Symbols got their names Metalloids Silicon Si Silex - Flint Germanium Ge Gemania - Germany

How Element Symbols got their names English Name Symbol Non-English Name and Meaning Metals Litium Li Lithos - Stone Sodium Na Natrium – Latin for soda ash Potassium K Kalium – Latin for potash Rubidium Rb Rubidius – Ruby Red Magnesium Mg Magnesia– location in Greece

Questions – Hand in 1. What makes mercury different from other metal elements? K (1) 2. Give an example of a metal element with the following properties. K (1) (a) It conducts heat and electricity. (b) It is shiny. (c) It reacts explosively with water. 3. (a) Compare and contrast the properties of silver, sulphur, and silicon. I (2) (b) How are these elements classified? 4. Give the symbols for the following elements. K (1) (a) nitrogen (b) nickel (c) lead 5. How can the meaning of the Latin name for gold help you to remember its element symbol? I (1)