Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chemistry - Coggle Diagram
Chemistry
-
Atomic structure
In the nucleus there protons and neutons and on the outside is an equal number of protons to electrons
-
Small number= Atomic number (electrons and protons) the bigger number= mass number (protons and neutrons) to find the number of neutrons is: neutrons= mass - atomic number
Electron= negative ,proton= positve,neutron= neutral charge
Bond energy calculations
when we break a chemical bond, this requires energy (endothermic). making bonds releases energy (exothermic). This tells us the energy required to break a bond
Two things we need to know to do the calculation. 1- the structure of the molecules involved
2-the energy level for each bond
On the side with the reactants the bonds are being broken but the side with the products a bond is being made . To break the bond means we must have the required amount of energy
and then do the equation +678 -862 = -184kJ and becasuse its negative the reaction is exothermic
-
Key words
Exothermic
gives of energy into the surroundings, this means exothermic energy changes are shown as negaitves
endothermic
in these reactions energy is gained fro the surroundings so endothermi energy changes are shown as positve,
Ions
How atoms become ions
an atom becaomes an ion when it reacts with another atom and they both end with full outer shells. For example if magnesuim has two in its outer shell and oxygen has six. Magnesiums two electrons would go to oxygens outer shell creating two ions
Ionic bonding
when two atoms react and both get full outer shells and become ions they bond together for example= a mangesuim atoms and chloride atom bond and form (MgCl 2) as two chlorides were needed to make ther be an outer shell in all the atoms involved
Group 1
The top element of group one is the least reactive as it has the strongest attraction to the neucleas so its more difficult to lose the electron however the bottom of group one is the most reactive because it has the weakest attartaction to the neucleus meaning it can easily give up it one electron making the reactive larger. The trend goes, Lithium, sodium, potassium,rubidium
Displacement reactions
A displacement reaction occurs when a more reactive element displaces, or pushes out, a less reactive element from a compound that contains the less reactive element. After a displacement reaction, the less reactive element is now pure and left uncombined.
Change in reactivity
When there is a change in reactivity this means that it will either change the product or the rate of the reaction