Atoms and Reactions

1. Mass=1.0
2. Charge= 1+

1. Mass= 1/2000
2. Charge=0

1. Mass= 1.0
2. Charge= 1-

Nota:

• Mass num,ber is thenumber of particles in thenucleus
• Atomic number is the number of proton in the nuclus of an atom
• Isotopes are atons of the same element with different numbers of neutrons
• An ion is a positively or negatively charges atom or group of atoms

Nota:

• Relative formula mass is the weighter mean mass of a formula unit compared with 1/12 of the mass of an atom of carbon-12
• Relativs atomic mass is the weighter mean mass of an atom of an element compared with 1/12 if the mass of an atom of carbon-12
• Relative iotopic mass is the mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12
• Relative molecular mass is thr weighter mean mass of a molecule compared with 1/12the mass of an atom of carbon-12

1. Ar(Br)= [(53x79)+(47x81)]/100=79.94

Nota:

• Amount of substance is the quantity whose unit is the mole. (Counting atoms)
• The Avogadro constant is the number of aoms per mole of the carbon-12 isotope
• A mole is the amount of any substance containing as many particles as there are carbon atoms in exacly 12g of carbon-12 isotope
• Molar mass is the mass per mole of a substance. The units of molar mass are gmol-1