Formula n Calcs(u1)

• Seven elements exist as diatomic molecules. The formulae for these

  elements are hydrogen (H2), oxygen (O2), nitrogen (N2), fluorine (F2),

  chlorine (Cl2), bromine (Br2) and iodine (I2)
• Compounds ending in ‘ide’ contain only 2 elements.
• 1= Mono, 2= Di, 3= Tri, 4= Tetra
• The formula for most compounds depends on the number of bonds each element in the compound forms. The number of bonds an element can form is called valency.
• Compounds that end with ‘ate’ or ‘ite’ contain three elements one of with is oxygen.
• The total mass of the atoms present in a formula is known as the formula mass.
• n = m x fm
• n = c x v
• % = m\fm x 100