atoms revision Flashcards
what is an element?
atoms of an element that exist on their own
what is a compound?
two or more different atoms
what is a mixture?
two or more different substances not chemically combined
what sub-atomic has no charge
neutron
what sub-atomic has a positive charge
proton
what sub-atomic has a negative charge
electron
what two sub-atomics are in the nucleus
protons and neutrons
what is the centre of the atom
nucleus
how do you tell if its a compund or element by looking at the letters
each element starts with a capital letter so if theres more than one its a compound
what name is given to different versions of atoms that have the same number of protons but different numbers of neutrons?
isotopes
how many electrons does it take to fill the first shell
2
how many electrons does it take to fill the second shell?
8
how many electrons does it take to fill the third shell?
8
desribe an isotope
an isotope of an element has the same number of protons but a different number of neutrons
what happens if the nucleus of an atom becomes unstable?
it rearranges itself to go to a table state again
what is a radioisotope?
a radioactive isotope of an element, an unstable atom that breaks down and releases particles and energy from the nucleus.
what can radioisotopes be used for?
tracers or used to kill cancer cells (radiotherapy)
what symbol does alpha radiation have?
α
what symbol does beta radiation have?
β
what symbol does gamma radiation have?
γ
what radiation has a positive charge?
alpha
what charge does beta have?
negative
what charge does gamma radiation have
no charge
what can alpha radiation be stopped by?
paper
what can aluminium stop?
beta radiation
does alpha penetrate low or high power
low
does beta penetrate low or high power?
medium
does gamma penetrate low or high power
high
what are some examples of uses of radiation in everyday life and what is their radiation?
Radiotherapy-y, tracers-b & y, smoke detectors-a, sterilisation of medical equipment and food-y
what happens when a proton is added into an atom
atomic number increases
what happens when a neutron is added into an atom
changes the atomic mass and element name
atomic number, protons and electrons all have…
the same number
atomic mass is…
protons and neutrons added together
neutrons is the atomic mass - …
protons
