19 solutions available
Question 5Compare all the proposed models of an atom given in this chapter.
Question 6Summarise the rules for writing of distribution of electrons in various shells for the first eighteen elements.
Question 7Define valency by taking examples of silicon and oxygen.
Question 8Explain with examples(i) Atomic number,(ii) Mass number,(iii) Isotopes and(iv) Isobars.Give any two uses of isotopes.
Question 9Na+ has completely filled K and L shells. Explain.
Question 10If the bromine atom is available in the form of, say, two isotopes 3579Br (49.7%) and 3581Br (50.3%), calculate the average atomic mass of...
Question 11The average atomic mass of a sample of element X is 16.2 u. What are the percentages of isotopes 816X and 818X in the sample?
Question 12If Z=3, what would be the valency of the element? Also, name the element.
Question 13Composition of the nuclei of two atomic species, X and Y, are given as under XYProtons =66Neutrons =68Give the mass numbers of X and Y....
Question 14For the following statements, write T for True and F for False.(a) J.J. Thomson proposed that the nucleus of an atom contains only...
Question 15Rutherford's alpha–particle scattering experiment was responsible for the discovery ofAtomic nucleusElectronProtonNeutron
Question 16Isotopes of an element haveThe same physical propertiesDifferent chemical propertiesDifferent number of neutronsDifferent atomic numbers
Question 17Number of valence electrons in Cl- ion are1681718
Question 18Which one of the following is a correct electronic configuration of Sodium?2, 88, 2, 12, 1, 82, 8, 1
Question 19Complete the following table.Atomic NumberMass NumberNumber of NeutronsNumber of ProtonsNumber of ElectronsName of the Atomic Species9 10...
Question 3Draw a sketch of Bohr's model of an atom with three shells.
Question 4What do you think would be the observation if the ∝–particle scattering experiment is carried out using a foil of a metal other than gold?
Question 1How will you find the valency of chlorine, sulphur and magnesium?
Question 2Write the electronic configuration of any one pair of isotopes and isobars.