Atomic Structure Flashcards
Define atom
The smallest part of an element that can exist
Define element
A substance made of only one type of atom
Define compound
A substance made of two or more different atoms chemically bonded together in fixed proportions
Define molecule
A substance made of more than one atom chemically bonded together
Define mixture
Two or more elements or compounds not chemically combined together. The chemical properties of each substance in the mixture are unchanged
State the type of mixture separated by filtration
An insoluble solid in a liquid
State the type of mixture separated by crystallisation
A soluble solid from a solution
State the type of mixture separated by simple distillation
A mixture containing two liquids or a solvent from a solid
State the mixture separated by fractional distillation
A mixture of more than two different solvents
State the type of mixture separated by chromatography
A mixture of solvents or solutions
How was the atom described prior to the development of the atom?
As a tiny sphere that could not be divided
What led to the development of the plum pudding model?
The discovery of the electron
What is the plum pudding model of the atom?
A ball of positive charge with negative electrons embedded into it
What experiment led to the development of the nuclear model?
The alpha scattering experiment
What were the two conclusions from the alpha scattering experiment?
The mass of the atom was concentrated at the centre and the nucleus was positively charged
How did Neils Bohr adapt the nuclear model?
By suggesting that electrons orbit the nucleus at specific distances
What evidence supported Neils Bohr’s adapted nuclear model?
The theoretical calculations of Bohr agreed with experimental observations
How were protons discovered in the nucleus?
Later experiments led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge
What was James Chadwick’s contribution to the atomic model?
He provided evidence to show the existence of neutrons within the nucleus
State the three subatomic particles
Protons, neutrons, electrons
State the relative charges of the subatomic particles
Protons: +1, neutrons: 0, electrons: -1
What is the atomic number of an atom?
The number of protons in an atom
What do all atoms of an element have in common?
The same atomic number
How can you find out how many protons are in an atom?
The smallest number on an element in the periodic table is the atomic number
