Difference between revisions of "Nuclear Model"

Revision as of 12:05, 24 November 2018

Key Stage 4

Meaning

A image of an atom in the Nuclear Model showing a small nucleus at the centre and an electron orbiting around the nucleus.

The Nuclear Model is a model of the atom which suggests there is a positively charged nucleus in the centre of an atom with electrons orbiting around the nucleus.

About the Nuclear Model

The Nuclear Model was first proposed by Ernest Rutherford after he successfully disproved the Plum Pudding Model of the atom using his alpha scattering experiment.

In the Nuclear Model most of the atom is empty space. The majority of the mass of the atom is concentrated in a small central nucleus. This central nucleus has a strong positive charge while negatively charged electrons orbit the nucleus.

Evidence for the Nuclear Model

In Rutherford's Alpha Scattering Experiment several observations about the path of alpha particles through a thin sheet of Gold foil that led to the development of the Nuclear Model:

Observation	Conclusion
Most of the alpha particles pass straight through the foil.	The atom must be mostly empty space.
Some of the alpha particles were deflected by a small angle.	The mass of the atom must be concentrated in an extremely small volume in the centre.
A very small number of alpha particles came back in the direction of the detector. (Deflected more than 90°.)	The centre of an atom must have a strong positive charge. The electrons must not be in the centre of the atom, they must be orbiting the nucleus.

@@ Line 12: / Line 12: @@
 {| class="wikitable"
 |-
-| style="height:20px; width:200px; text-align:center;" |'''Observation'''
+| style="height:20px; width:300px; text-align:center;" |'''Observation'''
-| style="height:20px; width:200px; text-align:center;" |'''Conclusion'''
+| style="height:20px; width:300px; text-align:center;" |'''Conclusion'''
 |-
-| style="height:20px; width:200px; text-align:center;" |Most of the [[Alpha Particle|alpha particle]]s pass straight through the foil.
+| style="height:20px; width:300px; text-align:center;" |Most of the [[Alpha Particle|alpha particle]]s pass straight through the foil.
-| style="height:20px; width:200px; text-align:center;" |The [[atom]] must be mostly empty space.
+| style="height:20px; width:300px; text-align:center;" |The [[atom]] must be mostly empty space.
 |-
-| style="height:20px; width:200px; text-align:center;" |Some of the [[Alpha Particle|alpha particle]]s were deflected by a small angle.
+| style="height:20px; width:300px; text-align:center;" |Some of the [[Alpha Particle|alpha particle]]s were deflected by a small angle.
-| style="height:20px; width:200px; text-align:center;" |The [[mass]] of the [[atom]] must be concentrated in an extremely small [[Volume (Space)|volume]] in the centre.
+| style="height:20px; width:300px; text-align:center;" |The [[mass]] of the [[atom]] must be concentrated in an extremely small [[Volume (Space)|volume]] in the centre.
 |-
-| style="height:20px; width:200px; text-align:center;" |A very small number of [[Alpha Particle|alpha particle]]s came back in the direction of the detector. (Deflected more than 90°.)
+| style="height:20px; width:300px; text-align:center;" |A very small number of [[Alpha Particle|alpha particle]]s came back in the direction of the detector. (Deflected more than 90°.)
-| style="height:20px; width:200px; text-align:center;" |The centre of an [[atom]] must have a strong positive charge.
+| style="height:20px; width:300px; text-align:center;" |The centre of an [[atom]] must have a strong positive charge.
 The [[electron]]s must not be in the centre of the [[atom]], they must be [[orbit]]ing the [[nucleus]].
 |}
-hey discovered that most of the [[Alpha Particle|alpha particle]]s went through in a straight line. A significant number were [[deflect]]ed and a very small number bounced off the [[Gold]] back towards the [[Alpha Particle|alpha]] source.