30.4.21 Flashcards
(25 cards)
describe the structure of an atom
the nucleus contains positive protons and neutral neutrons
the electron shells contain negative electrons.
what is the charge and mass of each of the particles in the atom
the mass of a proton is 1 and its charge is +1
the mass of an electron is 0 and its charge is -1
the mass of a neutron is 1 and the charge is 0
what are the sizes of the atom and the nucleus
the radius of an atom is about 1 x 10 -10m
the nucleus is 1/10000 of the size of the atom
where is most of the mass in the atom located
nucleus
describe the different parts of an element symbol
total number of protons and neutrons
total number of protons
chemical symbol representing the name of the element
describe how to find the number of neutrons in an atom
take the mass number away from the atomic number
describe what isotopes are
atoms with the same number of protons but a different number of neutrons
describe the plum pudding model of the atom
negatively charged electrons and a positively charged sphere
describe what happened in Rutherford’s alpha particle scattering experiment
alpha particles were fired at a piece of gold foil. most passed straight through but some bounced back.
how did the gold foil experiment show that most of the atom is made of empty space
that most of the electrons passed straight through the atom is made up of mostly empty space
how did the gold foil experiment show that most of the mass is in a positive nucleus at the centre of the atom
some of them bounced back, showing there was a positive nucleus that contained most of the mass
what did each of these people discover about the atom
a- james chadwick
b- nils bohr
a - James Chadwick showed that the nucleus is made of positive protons and neutral neutrons
b- Nils bohr showed that the electrons exist in energy levels around the atom
what is alpha radiation made of
the nucleus emits 2 protons and 2 neutrons
what is beta radiation made of
a neutron turns into a proton and released an electron
what is gamma radiation made of
the nucleus emits an electromagnetic ray but does not change
order alpha, beta and gamma from most to least ionising
alpha, beta, gamma
order alpha, beta and gamma from highest to lowest range
gamma , beta , alpha
what can stop each of the three types of radiation
alpha- sheet of paper or skin
beta- 5mm sheet of aluminium
gamma- few cm of lead
what is activity and which unit is it measured in
measured in becuerel (Bq)
what does the term ‘half life’ mean
half life is the amount of time it takes for half of the isotopes in the sample to decay
how do you work out the missing numbers in a decay equation
the numbers at the top and bottom need to add up
what is the symbol for alpha radiation
4 HE
2
what is the symbol for beta radiation
+ 0 e
-1
what is contamination and how do you protect against it
radiation gets on or inside the body or an object. it then caused continual irritation. the contaminated object becomes radioactive.
