P4 - Atomic Structure Flashcards
(25 cards)
What did John Dalton discover/believe?
Atoms were first described as solid spheres.
What did JJ Tomsom think?
Thomson suggested the plum
pudding model – the atom is a
ball of charge with electrons
scattered within it.
Who discovered the plum pudding model?
JJ Thomson
What year was the Alpha Particle exspirement?
1909
What did Neil Bohr believe?
Bohr theorised that the
electrons were in shells
orbiting the nucleus.
What did Chadwick discover?
Chadwick discovered neutrons in the nucleus.
What is an isotope?
An isotope is an element with the same
number of protons but a different number
of neutrons. They have the same atomic
number, but different mass numbers.
What does isotope decay mean?
Some isotopes are unstable and, as a result,
decay and give out radiation.
What is ionising radiation?
Ionising
radiation is radiation that can knock
electrons off atoms.
What is Alpha radiation?
It
is made from two protons and two neutrons.
What is Beta radiation?
Beta radiation is a fast moving electron
What is Gammna radiation?
A gamma wave is a wave of radiation
What stops Alpha radiation?
Skin
What stops Beta radiation?
aluminium
What stops Gamma radiation?
thick lead
What is half-life?
The half-life is the time taken for the number of radioactive nuclei in an isotope to
halve.
What happens in Alpha decay?
The atomic number goes down by two and its
mass number decreases by four.
What happens in beta decay?
A neutron turns into a proton and releases a an
electron. The mass of the nucleus does not change
but the number of protons increases.
What happens in Gamma decay?
There is no change to the nucleus when a radioactive
source emits gamma radiation.
What is the most dangerous radiation?
Alpha radiation is more dangerous inside
the body. It is highly ionising and able to
cause a lot of damage. Outside the body
it is less dangerous because it cannot
penetrate the skin.
Beta radiation is less dangerous inside
the body as some of the radiation is able
to escape. Outside the body it is more
dangerous as it can penetrate the skin.
Gamma radiation is the least dangerous
inside the body as most will pass out and
it is the least ionising. Gamma is more
dangerous outside the body as it can
penetrate the skin.
Name the 3 types of radiation.
alpha, beta and gamma
What protection methods do we put in
place to keep us safe from radiation
poisoning?
radiation suit, keeping your distance
from the source, only working with the
source for short periods of time, storing
sources in lead lined box
Why do some isotopes go through
nuclear decay?
they have and unstable nucleus / the
decay stabilises the nucleus
What is described as if an object
has a radioactive material introduced
into it?
contamination
