Yr9 recap test Flashcards
What did the discovery of the electron lead to?
The plum pudding model
What did the plum pudding model suggest about atoms?
That the atom was a ball of positive charge with negative electrons embedded in it
What did the results from the Rutherford and Marsden’s alpha scattering experiments lead to?
The plum-pudding model being replaced by the nuclear model.
In the nuclear atom model, what is the centre of the atom called?
The nucleus
What did the ‘alpha scattering’ experiment show?
. That all the mass of the atom was in the nucleus
. That all the positive charge of the atom was in the nucleus
How are electrons placed in the nuclear model?
The electrons were thought to orbit the nucleus, like planets around the sun.
What happened to most of the alpha particles in the ‘alpha scattering’ experiment? What did it prove?
Most of the alpha particles directed at thin gold foil passed through showing that
that all the mass of the atom was in the nucleus.
What happened to a few of the alpha particles in the ‘alpha scattering experiment’? What did it prove?
A few alpha particles were deflected or bounced back, suggesting the positive charge was concentrated at the
centre of each gold atom.
How did Neils Bohr adapted the nuclear model?
By suggesting that electrons orbit the
nucleus at specific distances
Where are electrons on the Bohr model?
The electrons are on energy levels or shells
What did later experiments (after Bohr) lead 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 the experimental work of James Chadwick provide the evidence to show?
The existence of neutrons within the
nucleus.
How long after the nucleus was discovered was neutrons discovered?
About 20 years after the nucleus became an accepted scientific idea.
What did the discovery of neutrons help explain?
The existence of isotopes
What is the nucleus of the atom made up of?
Protons and neutrons
What orbits around the nucleus of an atom?
Electrons
In an atom what is the number of electrons equal to?
The number of protons in the
nucleus.
Do atoms have an overall electric charge?
NO
What do all atoms of a particular element have?
The same number of protons
Where is most of the mass of an atom
The nucleus
What is an atom’s mass number?
The total number of protons and neutrons in an atom
What is the radius of an atom?
0.1 nm (1x 10-10 m)
What is the radius of the nucleus of an atom?
1/10 000 of that of the atom (about 1 x 10-14 m)
What is the atomic number of an element?
The number of protons in an atom
How are elements arranged in the modern periodic table.
In order of their atomic number (proton number)
How do you work out the number of neutrons in an atom?
Subtract the atomic number from the mass number
What are isotopes?
Atoms of the same element can have different numbers of neutrons
Do isotopes of an element have the same chemical properties
YES because they have the same electronic structure.
What is the relative atomic mass?
An average value that takes account of
the abundance of the isotopes of the element.
What is the relative atomic mass calculation