Atomic Structure for Cape Chemistry
ATOMIC STRUCTURE AND THE PERIODIC TABLE
Theoretical change with respect to Dalton’s atomic theory
1. In 1803, atomic theory was revived by John Dalton a) matter is made up of tiny particles called atoms which cannot be created, destroyed or split b) all atoms of one element are identical:- same mass and same chemical properties c) a chemical reaction consists of rearranging atoms from one combination to another.
d) When elements combine to form compounds, small whole numbers of atoms form molecules.
However this was proved to be not entirely correct. Atoms have been split as well as created i.e. nuclear reactions. Also there are isotopes, meaning that not all atoms of an element are identical.
Therefore theory was forced to CHANGE in regards to these observations contradicting to the theory put forward by Dalton.
The distribution of charge and mass in an atom
|Particle |Location |Mass |Charge |
|Electron |Orbitals |1/1837 unit |-1 unit |
|Proton |Nucleus |1 unit |+1 unit |
|Neutron |Nucleus |1 unit |0 |
[pic]
Terminology
|Term |Definition |
|Atomic/proton number |Number of protons in a nucleus of an atom |
|Nucleon/mass number |Sum of the number of protons and neutrons in the nucleus of an |
| |atom |
|Nuclide |Any atomic species of which the proton number and nucleon number |
| |are specified e.g. 126C and 94B are nuclides |
|Isotopes |Nuclides of the same element or atoms of the same element with |
|
Theoretical change with respect to Dalton’s atomic theory
1. In 1803, atomic theory was revived by John Dalton a) matter is made up of tiny particles called atoms which cannot be created, destroyed or split b) all atoms of one element are identical:- same mass and same chemical properties c) a chemical reaction consists of rearranging atoms from one combination to another.
d) When elements combine to form compounds, small whole numbers of atoms form molecules.
However this was proved to be not entirely correct. Atoms have been split as well as created i.e. nuclear reactions. Also there are isotopes, meaning that not all atoms of an element are identical.
Therefore theory was forced to CHANGE in regards to these observations contradicting to the theory put forward by Dalton.
The distribution of charge and mass in an atom
|Particle |Location |Mass |Charge |
|Electron |Orbitals |1/1837 unit |-1 unit |
|Proton |Nucleus |1 unit |+1 unit |
|Neutron |Nucleus |1 unit |0 |
[pic]
Terminology
|Term |Definition |
|Atomic/proton number |Number of protons in a nucleus of an atom |
|Nucleon/mass number |Sum of the number of protons and neutrons in the nucleus of an |
| |atom |
|Nuclide |Any atomic species of which the proton number and nucleon number |
| |are specified e.g. 126C and 94B are nuclides |
|Isotopes |Nuclides of the same element or atoms of the same element with |
|