Chapter 7 - Practice questions Flashcards
Explain how the Rutherford investigation led to the Plum Pudding model of an atom being replaced
Alpha particles are positively charged and the plum pudding model could not explain why a small fraction of the incident alpha particles entering an atom are deflected through very large angles.
The plum pudding model predicted that the all the alpha
particles would pass through the atom with little or no deflection.
Rutherford explained the observation that a small fraction
of the alpha particles are deflected through large angles
by assuming that the positive charge of the atom and most of the mass of the atom must be concentrated in a nucleus
Describe how the new proposed model of an atom was further changed by the work of the physicist Neils Bohr
Bohr worked that the electrons in the atom move round the nucleus in orbits at specific distances and specific energy levels.
He used his model to explain that an atom emits electromagnetic radiation when an electron in the atom moves to an orbit nearer the nucleus and emits electromagnetic waves in the process.
Complete the table of information for a radon atom.
Number of protons. 86
Number of electrons
Number of neutrons. 132
86
Calculate the mass number of this radon atom
218
Radon can exist in the form of many different isotopes. State the differences in the nuclei of these isotopes
different number of neutrons
The half-life of radon-222 is 3.8 days. Calculate how long a 48g sample of radon will last before it contains only 3g of radon and stops being effective
sample contains 3 g of radon
after 4 half-lives
15.2 days
Match each type of radiation to the correct description
alpha radiation/ beta radiation/gamma radiation
electromagnetic radiation/same as helium nucleus/ high-speed electron
alpha – same as helium nucleus
beta – high-speed electron
gamma – electromagnetic radiation
DO QUESTION 1 AND Question 4.2/4.3 in text page 95
DO QUESTION 1 AND Question 4.2/4.3 in text page 95
