Chem - The Atom Flashcards
What is an atom
The smallest part of an element that can exist
What are conpounds
The result of elements which have chemically reacted to form two or more elements chemically bonded
What is the plum pudding model?
A theory which suggests the atom is a sphere of positive charge with negative electrons inside of it
Before the discovery of the electron how was the atom envisioned
Like a sphere which could not be divided
What is the nuclear model of the atom?
The model resulting from the alpha particle scattering experiment which proved that the mass of an atom was concentrated in the centre in the charged nucleus
What is the positive charge inside of an atom?
Protons
What did Niels Bohr suggest?
That electrons orbit the nucleus at specific distances
What did James Chadwick discover?
That there were neutrons within the nucleus
Why did the evidence from the scattering experiment lead to a change in atomic model
It proved that the majority of the mass of the atom was based in the centre making the plum pudding model invalid
How small is the nucleus in relation to the atom
The radius of the nucleus is less than 1/10,000 of that of the atom
What are the relative masses of protons, neutrons and electrons?
Protons, 1
Neutrons, 1
Electrons, very small
How do you find the mass number of an atom?
Add the total protons and neutrons
What is an isotope of an atom
A variant of an element with more or less neutrons than the average
What is the atomic number of an atom
The total number of protons
How do you find the amount of electrons in an atom?
Atoms are neutral and therefore the number of electrons must = the number of protons otherwise known as the atomic number
