C1.01 The structure of an atom
C1.02 The relative mass and charge of protons, neutrons and electrons
| Particle | Relative mass | Relative Charge |
| Proton | 1 | +1 |
| Neutron | 1 | 0 |
| Electron | 1/1840 | -1 |
C1.03 Atomic number, mass number and relative atomic mass
Atomic number is equal to the number of protons or electrons in an atom.
Mass number is equal to the number of neutrons plus the number of protons in an
atom.
Relative atomic mass is the average mass of atom of an element compared
to a standard.
mass
number
12
symbol e.g. C
atomic
number
6
task C1.03
C1.04 Electronic structures of the first twenty elements in the periodic
table
Put electrons in shells so that the first is filled before the second etc
and
the first shell has a maximum of 2 electrons
the second shell has a maximum of 8 electrons
and the third shell has a maximum of 8 electrons
| atomic number |
element | electronic structure |
atomic number |
element | electronic structure |
| 1 | Hydrogen | 1 | 11 | Sodium | 2,8,1 |
| 2 | Helium | 2 | 12 | Magnesium | 2,8,2 |
| 3 | Lithium | 2,1 | 13 | Aluminium | 2,8,3 |
| 4 | Beryllium | 2,2 | 14 | Silicon | 2,8,4 |
| 5 | Boron | 2,3 | 15 | Phosphorous | 2,8,5 |
| 6 | Carbon | 2,4 | 16 | Sulphur | 2,8,6 |
| 7 | Nitrogen | 2,5 | 17 | Chlorine | 2,8,7 |
| 8 | Oxygen | 2,6 | 18 | Argon | 2,8,8 |
| 9 | Fluorine | 2,7 | 19 | Potassium | 2,8,8,1 |
| 10 | Neon | 2,8 | 20 | Calcium | 2,8,8,2 |
taskC1.04 make up your own atom
C1.05 Isotopes
Isotopes are atoms of the same element which have different numbers
of neutrons in their nuclei. As these are the same element the atoms all
have the same number of protons. For example hydrogen has 3 isotopes.
Each atom has 1 proton but a different number of neutrons.
Task C1.05
C1.06 Relative atomic mass of an element
Use relative mass of isotopes and their relative abundance. E.g. Chlorine has two
isotopes with mass numbers 35 and 37.
35
37
75% is Cl and 25% is Cl
17
17
Let there be 100 atoms
Total mass of 100 atoms = (75 * 35) + (25 * 37) = 3550
Average mass of an atom (relative atomic mass of chlorine) = Total
mass /Number of atoms
=3550/100
so relative atomic mass of chlorine = 35.5