C1 Chemical Reactions

Atoms are rearranged in a chemical reaction. 

Substances that react together are called reactants. 

Substances that are formed in a reaction are called the products. 

No atoms are created or destroyed in chemical reactions because total mass of the reactants is the same as the total mass of the products. 

Mass is conserved in a chemical reaction. 

Sodium = 2, 8, 1

Chlorine = 2, 8, 7 

Sodium = 2, 8, 1

Chlorine = 2, 8, 7 

Salt is the product of a sodium and chlorine. 

All atoms want a full outer shell, which is 8. 

Sodium has 1 electron on it's outer shell, and chlorine has 7. So they create an ionic bond so that they have a full outer shell. Sodium loses the electron on it's outer shell and chlorine gains it. The new configuration for sodium would be 2, 8 and for chlorine it would be 2, 8, 8. 

Ionic Bonds are one type of chemical bonds - the others being covalent and metallic. 

Occurs between metals and non-metals. 

Get an electrical charge - one positive and one negative because opposites attract. 

In Sodium Chloride the sodium atom gives one electron to the chlorine atom so that they both have full outer shells (8) 

Sodium becomes positive as it has lost an electron 

Chlorine becomes negative as it has gained an electron

These two atoms take on electrical charges - called ions. 

Atoms have no charge, ions have a positive/negative charges. 

No transfer of electrons. 

Electrons shared. Happens with non-metals. 

2 Hydrogen atoms covalent bond to make H2 so that they have a full outer shell. 

can be displayed as H -- H 

H20 is 2 hydrogen atoms and one oxgen atoms so that they have a full outer shell. 

Can be shown as   O 

                          H        H 

NH3 (Ammonia) contains 3 hydrogen atoms and 1 nitrogen.

Can be shown as    H -- N -- H 

                                        !

                                       H 

Reactants ----> products 

NEVER use an = sign ALWAYS an ----->

Must write the whole equation on one line 

A balanced equation has the same number of each type of atom on both sides of the arrow. 

H2 + C2 ---> HCL 

is equal to...

H H + CL CL ---> H CL 

Find a combination of elements which makes the equation balanced. 

the answer is... 

H2 + C2 ---> 2HCL

because it leaves you with the same amount of each element. 

Mass can neither be created or destroyed