Atomic Structure And Radioactivity Flashcards
Radius of an atom
1x10{-10}
What is the radius of the nucleus compared to the radius of the atom
Less than 1/10000
What does the nucleus contain
Protons and neutrons
Is the nucleus a positive or negative charge
Positive
Do atoms have a charge
They have no overall charge
Are electrons and protons equal
Yes
What does the mass number tell us
The number of protons and neutrons added together
How do you calculate the number of neutrons
Atomic number - mass number
Isotope
Isotopes are atoms of the same element that have differ numbers of neutrons
Ion
Charged atoms
They have lost or gained electrons
What is the plum pudding model
A ball of positive charge with negative electrons embedded in it
J.J Thomson
What is the gold foil experiment / alpha scattering experiment / nuclear model
Most alpha particles went straight through the gold foil
Therefor atoms are mainly space
Sometimes alpha particles bounced straight back or were deflected
Rutherford
What was Bohr suggestion
Electrons orbit (energy levels/shells) the nucleus at specific distance
Radioactivity
Some isotopes have an unstable nucleus
To become stable, the nucleus gives out radiation
This is called radioactive decay
Activity
The activity is the rate at which a source of unstable nuclei decay
Name the 3 types of radiation
Alpha
Gamma
Beta
What is alpha penetrating power
It can travel through paper
What is beta penetrating power
Through aluminium
What is gamma penetrating power
Through lead
What is alpha ionising power
Very strong
Beta ionising power
Quite strong
Gamma ionising power
Weak
Alpha decay
Alpha = 4/2
Beta decay
Beta = 0/-1
