Chapter 1: Atomic structure and the periodic table

Atoms, formulae and equations:

-ALL substances are chemicals

-ATOMS and MOLECULES

-Atoms join by sharing electrons

-if 2(+) atoms join they form a molecule (eg water & oxygen)

-FORMULAE

-see elements in compound by looking at formula (eg magnesium oxide MgO contains Magnesium and Oxygen)

-Group 1 & Group 7 elements and Group 2 & Group 6 elements combine make compounds in a fixed ratio 1:1 

-Group 2 & Group 7 elements combine make compounds in fixed ratio of 1:2, element need '2' of has a little '2' after it eg…