C1- Atomic Structure Flashcards
What is an atom?
An atom is the smallest part of an element that can exist.
How are compounds formed and separated?
Compounds are formed from elements by chemical reactions.
What is a compound?
Compounds contain two or more elements chemically combined in fixed proportions and can be represented by formulae using the symbols of the atoms from which they were formed.
What are the two main types of chemical equation?
Chemical reactions can be represented by word equations or equations using symbols and formulae.
What is a mixture?
A mixture consists of two or more elements or compounds not chemically combined together. The chemical properties of each substance in the mixture are unchanged.
How are mixtures separated?
Mixtures can be separated by physical processes such as filtration, crystallisation, simple distillation, fractional distillation and chromatography. These physical processes do not involve chemical reactions and no new substances are made.
What is the plum pudding model?
The plum pudding model suggested that the atom is a ball of positive charge with negative electrons embedded in it.
Why was the plum pudding model replaced by the nuclear model?
The results from the alpha particle scattering experiment led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged. This nuclear model replaced the plum pudding model.
What did Niels Bohr do to the nuclear model and why?
Niels Bohr adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances.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. The name proton was given to these particles.
What did James Chadwick do?
James Chadwick provided the evidence to show the existence of neutrons within the nucleus.
What are the subatomic molecules of an atom?
Protons, Neutrons and Electrons
What are the subatomic particle’s relative charges?
Protons= +1 Neutrons= 0 Electrons= -1
How do you calculate the number of protons in an atom of an element?
The number of protons in an atom of an element is its atomic number.
How big are atoms?
Atoms are very small, having a radius of about 0.1 nm (1 x 10-10 m).
The radius of a nucleus is less than 1/10 000 of that of the atom (about 1 x 10-14 m).
Where is the mass of an atom, and which subatomic particles have mass?
Almost all of the mass of an atom is in the nucleus.
The sum of the protons and neutrons in an atom is its mass number.
Protons= 1
Neutrons= 1
Electrons= Very Small
