Lesson 7 October 5 th , 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

solids

(5) and only one is liquid.

gasses

(11) or  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

conduct electricity well.

because they do not

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 Hydrogen Helium Neon Argon Fluorine Chlorine He Ne Ar F Cl

Non-metals

H Hydro genes –water generating Helios – the sun Neos – new Argos – inactive or idle Fluere – Flowing 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 Litium Sodium Potassium Rubidium Magnesium Li Na K Rb Mg

Metals

Lithos - Stone Natrium – Latin for soda ash Kalium – Latin for potash Rubidius – Ruby Red 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)