C1 Atomic Structure Flashcards
All substances are made of…
Atoms
An atom is the…
Smallest part of an element that can exist
Elements are…
Substances that contain only one type of atom
Before the discovery of the electron atoms were thought to be…
Small spheres that could not be divided
The discovery of the electron led to…
The plum pudding model which suggested the atom is a ball of charge with negative electrons embedded in it.
The results of the alpha particle scattering test concluded that…
The mass of the atom was concentrated in its centre ( the nucleus ). This nuclear model replaced the plum pudding model.
Niels Bohr adapted the nuclear model by…
Suggesting that electrons orbit the nucleus at specific distances.
After the nuclear model adaptation came a set of experiments that gave the idea that…
The positive charge of a nucleus could be subdivided into many smaller particles. They each had the same amount of positive charge. These particles were named protons.
The work of James Chadwick led to the discovery of…
Neutrons within the nucleus. These discoveries took place 20 years after the acceptence of the idea of the nucleus.
The relative electrical charges of the particles in atoms are
Proton- +1
Neutron- 0
Electron - -1
In an atom…
The number of protons is equal to the number of electrons. This means atoms have no overall charge.
The number of protons in an element is the…
Atomic number of the element
Atoms have a radius of about…
0.1nm
Almost all the mass of an atom is…
Inside the nucleus
The relative masses of protons,neutrons and electrons are…
Proton- 1
Neutron- 1
Electron- Very Small
