[YEAR 9] Dot and Cross Diagram Section
All you need to know about dot and cross diagrams from the start to the end according to the official syllabus.
Welcome!
This course is going to explain all about dot and cross diagrams. You are most likely here because your teacher has directed you here for help on it. No problem! The below is a taster of what the lectures will be like here we go;
What is a dot and cross diagram?
A dot and cross diagram is a representation for an equation that shows - the amount of atoms among that element, how many atoms it shares between elements and also the connection between them. From pictures you might have seen it may look complicated but when you get started it is easy as peas! You just need to be careful... Do not worry as we have something to help later on.
How do I go about answering one?
A question that will mean you have to draw a dot and cross diagram would usually look like this:
Draw a dot and cross diagram for CS2
Then what you would do is follow the rules below to help you. Your teacher should have of issued a sheet with these rules already on. Make sure you don't lose that sheet because it is vital in this sequence. If not they are shown below;
Rules For Dot and Cross Diagrams
1.) Look at the formula you have been given.
2.) Decide how many atoms there are per element.
3.) Draw the circles (make sure they are overlapping) if there is more than one attach that amount to the first element).
4.) Look up the elements on the periodic table.
5.) Decide how many outer shell electrons each element has.
6.) Decide how many more are needed (normally it should add up to 8 apart from Hydrogen that is 2).
7.) This is the number of dot and cross pairs (a dot and cross pair is one pair OF one dot and one cross).
8.) Draw these pairs sharing them between the overlaps.
9.) Add more dots and crosses around the circles (individually) until the total number is 8 or 2 for Hydrogen.
Still struggling?
Here is a video from QEGS Chemistry to help! Mainly for visual learners...