# Shared Flashcard Set

## Details

Atomic structure AQA GCSE
Module 2 revision cards for atomic structure
17
Physics
Not Applicable
04/24/2008

Term
 Describe the structure of an alpha particle in as much detail as possible.
Definition
 An alpha particle can be described as either the nucleus of a Helium atom or as 2 protons and 2 neutrons joined together.
Term
 In Rutherford's famous experiment most of the alpha aprticle went straight through the thin piece of gold film in a straight line.  What did Rutherford learn about the structure of the atom from this?
Definition
 The fact that so many alpha particles went straight through means that the vast majority of an atom must be empty!
Term
 In Rutherford's famous experiment some of the alpha particles went through the thin piece of gold film but were also deflected (changed direction).  What did Rutherford learn about the structure of the atom from this?
Definition
 The positively charged alpha particles were being repelled by something which was also positively charged (we now call this the nucleus)
Term
 In Rutherford's famous experiment very few of the alpha particle actually were reflected blackwards of the gold film in a straight line.
Definition
 The alpha particles were colliding with something which wasa.  Very dense because they reflected back off it.b.  something very small because it did not happen very often.Rutherford had discovered the nucleus!
Term
 Describe the structure of an atom in as much detail as possible.
Definition
 At the centre of an atom is a very small, very dense and positively charged region called the nucleus.  This contains particles called protons and neutrons.Orbitting the nucleus are much smaller particles called electrons, they exist in things called shells.
Term
 Describe the mass and electric charge properties of electrons, protons and neutrons.
Definition
 Protons and neutrons have roughly the same mass (neutrons are slightly heavier), electrons have about 1/2000 of the mass of a proton or neutron.Protons have positive charge.Electrons have negative charge.Neutrns are neutral, they have no charge.
Term
 What does the mass or nucleon number tells us about the structure of a nucleus?
Definition
 The mass or nucleon number is the total number of protons and neutrons in the nucleus.
Term
 What does the atomic number tells us about the structure of the nucleus?
Definition
 THe atomic number is the number of protons found in the nucleus.
Term
 How can you work out the number of neutrons found within the nucleus?
Definition
 Subtract the atomic number from the mass number.
Term
 An atom is neutral so what does this tell you about the number of protons and electrons?
Definition
 There must be an equal number of protons and electrons so that the negative charge cancels out the positive charge to make the atom neutral.
Term
 What is an ion?
Definition
 An ion is an atom which has gained or lost electrons.This makes the atom either positively charged (if it lost an electron) or negatively charge (if it gained an electron).
Term
 What is an isotope?
Definition
 Isotopes are atom which have the same number of protons but different numbers of neutrons.  For exampleCarbon 12 has 6 protons and 6 neutronsCarbon 13 has 6 protons but 7 neutronsCarbon 14 has 6 protons but 8 neutrons.They are all isotopes.
Term
 What is a beta particle?
Definition
 A very fast moving (high amount of kinetic energy) electron.
Term
 Where do alpha particles, beta particles and gamma rays come from?
Definition
 They are all emitted from an unstable nucleus of an atom.
Term
 What will happen to the mass and atomic number if an alpha particle is emitted?
Definition
 An alpha particle is made up of 2 protons and 2 neutrons.Therefore the mass number will go down by 4 and the atomic number by 2, an atom of a new element will have been formed.
Term
 What will happen to the mass and atomic number if a beta particle is emitted?
Definition
 If a beta particle is emitted from the nucleus then a neutron has changed into a proton and electron (the beta particle).Therefore the atomic number will have gone up by one, the mass number will stay the same.An atom of a new element will have been formed.
Term
 What will happen to the mass and atomic number if a gamma ray is emitted?
Definition
 A gamma ray is pure energy.  Nothing will have happended to the neutrons and protons in the nucleus other than they have lost some energy.Therefore the mass and atomic number stay the same.
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