第二章 Basic Properties of Atom：With modern atomic theory, an atom is composed by a nucleus and electrons. The mass of an atom is too small, which can be expressed by many convenient units. Their sizes are around nanometer, which can be measured by many experimental methods. The electron was discovered by J. J. Thompson. At beginning of 20 century, there were several theoretical models about the atom. Geiger and Marsden used the alpha particle to strike the golden and found that the large space of atom is empty. Rutherford developed a scattering formula to explain the Geiger-Marsden experiment and proposed the planet model.2.1What is an atom:An atom is composed of a nucleus and electrons.[单选题]The mass of a single iron atom is 9.3 × 10–23 g. Determine the number if iron atoms in regular cube that measures exactly 10 cm on an edge. The density of iron is 7.86 g/cm3 ( )
2.2The size of an atom:The mass of atom is very tiny. There many units can be used to describe the mass of atom.
2.3Determination of the size of the atom:There many experimental technologies to measure the size of atom.
2.4The discovery of electron:In 1897, J. J. Thompson discovered the electron in cathode ray.
2.5The atom models at beginning of 20 century:The plum pudding model and Saturnian model of atom are introduced.
2.6Results of plum pudding model:Most of alpha directly cross the golden atom. Some of them scatter at very large angle.
2.7Trajectories in scattering:In microscopic world, the cross section is easily to describe the collision.
2.8The cross section:Rutherford proposed a new model to explain the atom.
2.9The difference between Two models:The nuclear radius can be obtained from Rutherford scattering formula.
2.10Exercise:There several exercises about the basic properties of atom.
选项:[3.5 × 1025 , 8.5 × 1025, 7.5 × 1024 , 4.2 × 1026]
[单选题]According to structure of atom electron should fall in ( )? 选项:[outer environment, shell , nucleus, space]
[单选题]For an 8.0-MeV α particle scattering from a gold atom ( Z = 79 ) of radius 0.135 nm, the largest scattering angle, θ is ? ( ) 选项:[
, 
, 
, 
] [单选题]State the mass of Avogadro’s number of atoms for Copper ( ). 选项:[127.10 g, 23.22 g, 63.55 kg, 63.55 g ]
[单选题]What fraction of a beam of 7.7-MeV alpha particles incident upon a gold foil 3.0×10-7 m thick is scattered by less than 1°? ( ) 选项:[ 0.67 , 0.05 , 1.35 , 0.84]
[单选题]The mass of a proton is ( ) 选项:[10.07 u, 3.344× 10-27 kg, 0.511 MeV, 1.673× 10-24 g ]
[单选题]For aluminum ( Z2 = 13) and gold ( Z2 = 79 )targets, what is the ratio of α particle scattering at any angle for equal numbers of scattering nuclei per unit area? ( ) 选项:[0.03 , 1.47 , 36.93, 134.5]
[单选题]A 5.0-MeV alpha particle approaches a gold nucleus with an impact parameter of 2.6×10-13 m. Through what angle will it be scattered? ( )
选项:[10° , Plasma physics , Environment, Astrophysics]
[单选题]In Rutherford atomic model alpha particles were stroked on ( ) 选项:[aluminum , gold , titanium, silver]
[单选题]Which of the following is not a valid conclusion from Rutherford’s alpha particle scattering experiment? ( ) 选项:[The mass of the atom is mostly concentrated in the nucleus , The nucleus must be positively charged , The nucleus must be very small compared to the atom, The atom is mainly empty space ]
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