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Physics Gcse Higher 9-1 > Atomic Structure > Flashcards

Flashcards in Atomic Structure Deck (15):

Describe our current nuclear model of the atom

-tiny nucleus
-contains protons and neutrons
-mostly empty space
-electrons are fixed on energy levels on the outside of the nucleus


What is an isotope

An isotope of an element are atoms with a different number of neutrons but the same number of protons


Which are the most ionising alpha particles or gamma

Alpha particles


Outline why beta emitters rather than alpha or gamma emitters are used to test the thickness of sheets of metal

Beta emitters are not immediately absorbed like alpha radiation and do not penetrate as far as gamma therefore variations of the thickness of the sheet significantly affect the amount of radiation passing through beta radiation


Name one type of nuclear radiation the particles of which are electrons



Name the type of nuclear radiation that is an electromagnetic wave



What is the difference between radioactive contamination

Irradiation does not make something radio active
Contamination makes something radio active
Contamination is caused by direct contact
Irradiation is caused by background radiation


Why is contamination by an alpha source more dangerous to humans than irradiation

Substances witch a short half life decay very quickly and emit high amounts of radiation which is highly ionising


Briefly describe how the model of an atom has changed over time

- 1804 John Dalton thought matter was made up of tiny spheres
- 1900s J.J Thompson discovered particles called electrons he suggested atoms were spheres of positive charge with tiny negative electrons stuck in them (plum pudding)
- Rutherford conducted the Alpha scattering experiment in which he discovered there is a tiny positive charge which was the nucleus and that most of the atom is empty space
-Bohr discovered electrons orbit around the nucleus


Who provided the evidence to suggest the existence to suggest the existence of the neutron

James Chadwick


True or false atoms have no overall charge



What happens to an atom if it loses one or more of its outer electrons

It becomes a positively charged ion


Which number defines what an element an atom is: the atomic number or the mass number

Atomic number


What is the atomic number

The number of protons


True or false isotopes have different mass numbers