Stability and change - Inside the nucleus Flashcards
What is an Isotope?
All atoms of a particular element have the same number of protons but sometimes the number of neutrons in atoms of the same element is different. They have the same atomic number but different mass number.
Two more facts about Isotopes
Many elements exist as two or or more isotopes.
Isotopes have the same chemical properties but different masses.
What is Nuclide notation?
It is used to represent the isotopes of an element and includes the atomic and mass number.
What is stable and unstable atoms?
Stable atoms - are when the protons and neutrons found in the nucleus are held together very strongly.
Unstable atoms - Are when the neutrons and protons in the nucleus are not held together very strongly.
What is radioisotopes?
Unstable isotopes decay to form other elements, these isotopes are said to be radioactive and are called radioactive isotopes or radioisotopes.
How and why does an atom become unstable?
If the size of an atom increases there tends to be more neutrons than protons in the nucleus. The difference in the number of neutrons compared to protons increases as the atom gets bigger and bigger, as a result the element becomes unstable.
What’s the equation to calculate the relationship between mass and energy? And what do they represent
E=mc2….. E - energy, m- mass and c is a constant.
What is natural radioactivity?
It is radioactivity emitted from matter without energy being supplied to atoms.
What is nuclear radiation?
It is radiation from the nucleus of an atom consisting of alpha or beta particles or gamma rays.
Description and penetration and danger to health caused by Alpha radiation?
Description - Helium nuclei that contain two protons and two neutrons so they are positively charged.
Danger to health - Cannot be travelled through materials easily and can be stopped by a sheet of paper or human skin, can cause serious damage if breathed in or eaten.
Description and penetration and danger to health caused by gamma rays?
Description - Not particles but bursts of energy released after alpha or beta particles are emitted, travel at the speed of light
Danger to health - Highly penetrating, can cause serious and permanent damage to tissue and can only be stopped by thick shield of lead or concrete.
Description and penetration and danger to health caused by Beta radiation?
Description - Same size and mass as electrons can have a negative or positive electric charge can travel as high as speed of light.
Danger to health - Can penetrate human skin and damage tissues but cannot penetrate think layers of plastic or wood.
What is a half life?
Half life is the time taken for half of the radioactive atoms in a sample to decay, that is change into atoms or a different element.
