Flashcards
Chemistry- the atom
Cards in this deck (20)
- 1What is the radius of an atom?0.1 manometers (1 x 10 to the power of -10 nm)
- 2How big is a nanometer?A nanometer is one billionth of a meter
- 3Where is it in the atom?The middle of the atom
- 4What does the nucleus contain?Protons and neutrons
- 5What is the radius a the nucleus?1 x 10 to the power of -14m (around 1/10000 of the radius of an atom)
- 6What is the charge of a nucleus?A nucleus is positively charged because of the protons
- 7What are the properties of protons, neutrons and electronsProtons are heavy and positively charged
Neutrons are heavy and neutral, electrons are tiny and negatively charged - 8Electrons.Electrons move around the nucleus in electron shells, they are tiny in comparison to protons or neutrons, the volume of their orbits determines the size of the atom, electrons have virtually no mass
- 9The number of protons is equal to the number of electrons. True or falseTrue
- 10Why are atoms neutral?Atoms are neutral because they have the same number of protons and electrons. This charge on electrons is the same size on the protons but opposite, so the charges cancel out
- 11What she John Dalton think atoms were?John Dalton describes atoms as solid spheres- he proposed that these spheres made up different elements
- 12What did JJ Thompson propose?JJ Thompson measured the charge and mass of atoms, he concluded that atoms must contain smaller, negatively charged particles-electrons. From these measurements he concluded that electrons couldn’t be solid spheres.
- 13What was the plum pudding model?The plum pudding model showed atoms as balls of positive charges with electrons inside
- 14What was the experiment that disproved the plum pudding model?The alpha particle scattering experiments
- 15How did the alpha particle scattering experiments disprove the plum pudding model?Ernest Rutherford and Ernest Marsden fired positively charged alpha particles at gold foil. If the plum pudding model was correct the particles would pass through or a few to be deflected. This was because the positive charges of each atom was thought to be spread out across the plum pudding modelled atom. The experiment showed that while most of the particles pass through the gold sheet, more were deflected than expected, some even deflected backwards. This meant that they had to be hitting something. If they were fired directly at the nucleus they were deflected backwards. Otherwise they passed through empty space. Rutherford then cane up with the nuclear model.
- 16What does the nuclear model of the atom look like?A tiny positively charged nucleus where mode of the mass is concentrated. Most of the atom is empty space.
- 17Why did Rutherford think that atoms would collapse?Because the electrons ‘cloud’ around the nucleus of the atom so would be attracted to it
- 18What did Neils Bohr propose?That electrons orbited around the nucleus and were contained in fixed shells.
- 19How were protons discovered?Further experiments showed that the nucleus can be divided into smaller particles which have the same charge as the hydrogen nucleus. These particles were called protons
- 20How was the neutron discovered?James Chadwick carried out an experiment which shorted evidence for neutrons.Chadwick’s model is similar to the modern nuclear model
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- Flashcards on Chemistry- the atom , created by Elizabeth Quigg on 13/11/2017.
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- Elizabeth Quigg
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