CBSE Class 9 class9_atom_structure — practice questions
27 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice CBSE Class 9 class9_atom_structure in the app →Atomic number Z of an atom equals:Isotopes of an element have the same:Canal rays were discovered in 1886 by:The mass of a proton is about how many times that of an electron?The charge on a proton is taken as:Who first proposed a model of the atom?In Thomson's model the electrons are set in a sphere that is:Rutherford directed alpha particles at a thin foil of:In the scattering experiment, most alpha particles:Roughly how many alpha particles rebounded?Rutherford concluded that most of the space inside an atom is:The rebounding particles showed that positive charge and mass sit in a:The neutron was discovered in 1932 by:Neutrons are present in the nucleus of all atoms except:The distribution of electrons into shells was suggested by:The maximum electrons in a shell is given by which formula?The maximum number of electrons in the outermost shell is:An atom with eight electrons in its outer shell has a valency of:Protons and neutrons together are also called:The mass number of an atom is the sum of its protons and:The mass number is denoted by which letter?The atomic number is denoted by which letter?Elements are defined by the number of their:For hydrogen the atomic number Z equals:Atoms of the same element with different mass numbers are:Atoms with the same mass number but different atomic numbers are:The mass of carbon is 12 u because it has 6 neutrons and: