atomic structure Flashcards
what is the relative mass and charge of protons, neutrons, and electrons
protons = 1 and +1
 neutrons = 1 and 0
electrons = 1/1860 and -1
What is the radius of an atom
One times 10 to the power of -10
What is the radius of a nucleus
Less than 1/10,000 of the radius of the atom
What is an isotope
Atoms of the same element with the same number of protons and a different number of neutrons
What is an ion
Elements That have lost or gain electrons
What is the nucleus
The centre of the atom containing protons and neutrons
What is a half life
The time it takes for the number of nuclei of the isotope in a sample to half
What is irradiation
The process of exposing an object to ionising radiation
What is contamination
The unwonted presence of materials containing radioactive atoms or other materials
What is fusion
The joining of two like nuclei to form a heavier nucleus
What is fission
The splitting of large and unstable nucleus 
Alpha particles
Made from two protons and neutrons, blocked by paper and skin
Beta particles
High-speed electron, blocked by 5 mm of aluminium foil
Gamma rays
Electromagnetic radiation from the nucleus, blocked by lead
Radioactive decay
Is random and not possible to predict
what is the history of the model of an atom?
John Dalton published his ideas about atoms in 1803. He thought that all matter was made of tiny particles called atoms
J J Thomson carried out experiments and discovered the electron. This led him to suggest the plum pudding model of the atom.
Ernest Rutherford’s scattering experiment
what was Rutherford’s scattering experiment?
Ernest Rutherford designed an experiment to test the plum pudding model. In the experiment, positively charged alpha particles were fired at thin gold foil. Most alpha particles went straight through the foil. But a few were scattered in different directions. This evidence led Rutherford to suggest a new model for the atom, called the nuclear model.
