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11YA - Homework for the weekend beginning 28th September.

Cut and stick the passage below into word and fill in the missing words-see bottom of page for help. 

Either print off and hand in on Monday or e-mail to pwest@blueyonder.co.uk

The Periodic Table Song

fig 1

fig 2

fig 3

fig 4

fig 5

fig 6

fig 7

fig 8

There are three types of bond:

Covalent Bonds are formed when atoms from the _ _ _ _ side of the try to become stable.  They do this by _ _ _ _ _ _ _ electrons. Covent bonds are very _ _ _ _ _ _ and appear as single bonds, double bonds and even triple bonds.  Each covalent bond consists of a shared  _ _ _ _  of electrons. Methane ( fig 5 ) and Diamond ( figs 1, 2 and 6) are substances with covalent bonds.

Ionic Bonds such as those formed between sodium and chlorine, involve complete electron _ _ _ _ _ _ _ _ . This produces charges 'atoms' which are referred to as _ _ _ _.  There are positive ions and negative ions.  Metals always form _ _ _ _ _ _ _ _  ions and non-metals usually form _ _ _ _ _ _ _ _  ions. The 3-D structure of sodium chloride is shown in (fig 3)

Weak London Forces also known as van-der-waals forces are very weak and _ _ _ _ _ _ broken by heat energy.  These forces hold covalent molecules together at low temperatures. When ice forms it is these forces that make the water molecules come together to form a _ _ _ _ _. Similar weak forces hold the layers of graphite loosely together    (fig 7) making it an idea lubricant and drawing medium. (fig 4)

There are four main types of structure:

Molecular Structures - such as in methane , _ _ _ _ _ _ _ _ and ammonia (fig 5) .  Substances with molecular structures usually exist as gases or liquids with low boiling points.  Occasionally solids have molecular structures.  The most notable being sulphur, which has molecules with 8 sulphur atoms in the shape of a _ _ _ _.

Giant Ionic Structures - such as sodium _ _ _ _ _ _ _ _, copper sulphate and other water soluble crystalline compounds.  These consist of a vast array of oppositely charged ions forming a gigantic structure.  Ionic Crystals don't have particularly strong bonds but the vastness of their structure gives them strength.  They have high melting points and are usually soluble in water.

Giant Molecular Structures such as _ _ _ _ _ _ _ _ , diamond (fig 1,2 and 3) and silicon dioxide (sand) have giant molecular structures.  A perfect diamond with no flaws could be regarded as a SINGLE molecule containing billions and billions of atoms joined with strong covalent bonds.  These structures are usually very strong due to the strength of both the bond AND the structure.

Words

chlorine       ring        easily      transfer     same    chloride        ions        sharing    strong        positive

pair        negative      graphite      solid         

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