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physics
Fichas del conjunto (25)
- 1What is the size of an atomthey are very small, with a radius of about 1x10-10 meters
- 2describe the structure of an atomConsists of a positively charged nucleus composed of both proton and neutrons surrounded by negatively charged electrons
- 3What part of the atom makes up most of its massthe radius of a nucleus is less than 1/10000 of the radius of an atom. Most of the mass of an atom is concentrated in the nucleus
- 4how are the electrons in an atom arrangedthey are arranged at different distances from the nucleus
- 5why do atoms have no overall chargethe number of electrons is equal to the number of protons in the nucleus. atoms have no overall electrical charge
- 6What info does the atomic number of an atom giveall atoms of a particular element have the same number of protons. the number of protons in an atom of an element is called its atomic number
- 7what info does the atomic mass of an atom givethe total number of protons and nuetrons
- 8what is an isotopeatoms of the element with the number of protons but different neutrons
- 9what happens to an atom when it loses electronsthey turn into positive ions
- 10what happens to an atom when it gains electronsatoms turn into negative ions
- 11what did scientists think the atom was like before the discovery of electronsthey were thought to be tiny spheres that could not be divided
- 12describe the plum pudding modelit is a ball of positive charge with negative electrons in it
- 13what was learnt about the atom from the alpha scattering experimentthe mass of an atom was concentrated at the centre and that the nucleus was positively charged and very small in compared with the atom
- 14how did Bohr modify our understanding of the structure of the atomhe adapted the nuclear model by suggesting the electrons orbit the nucleus at specific distances
- 15why do the nuclei of some atoms give out radiationas it changes to become more stable
- 16what does does activity mean and what is it measured inis the rate at which source of nuclei decay. its measured in becquerel(Bq)
- 17describe an alpha particle and give its mass a chargean alpha particle(a) — this consists of two neutrons and two protons, has a 2+ charge and a mass of 4
- 18what is a beta particlea beta particle(B) — a high speed electron ejected from the nucleus as a neutron turns into a proton
- 19What is a gamma rayA gamma ray (Y) — electromagnetic radiation from the nucleus. (No change in in numbers of protons, neutrons, electrons
- 20What does ionising ability meanthis the ability of of a radioactive particle to knock electrons from an atom
- 21describe the ionising and penetration ability of an alpha particleAlpha particles are highly ionising but can only penetrate through 1 - 5cm of air
- 22describe the ionising and penetration ability of an gamma particlehas a low ionising ability but is highly penetrating. its radiation can br blocked but which lead
- 23What is half-lifethe half-life of a radioactive isotope is the time it takes for the number of nuclei of the isotope in a sample to halve, or the time it takes for the count rate from a sample containing the isotope to fall to half its initial level
- 24how can we find out the half-life of a radioactive isotopecan be determined from a exponential decay graph
- 25what is irradiationit is the process of exposing an object to nuclear radiation. the object does not become radio active
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- GCSE Physics Fichas sobre physics , creado por Jael R-C el 02/12/2018.
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- Jael R-C
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