PlayTest #3- Army public school (Classic)

The electrons present in the outermost shell are called

• Valency electrons

• Octate electrons

• Duplet electrons

• Valence electrons

The isotope used to remove the brain tumours and treatment of cancer is

• U-235

• Na-24

• Iodine

• C0-60

The isotope deuterium of hydrogen has

• No neutrons and one proton

            

• One neutrons and two protons

          

•      One electron and two neutron

         

• One proton and one neutron

In an alpha scattering experiment, few alpha particles rebounded because

• Most of the space in the atom is occupied

           

• Positive charge of the atoms very little space

          

•   The mass of the atom is concentrated in the centre

        

• All the positive charge and mass of the atom is concentrated in small volume

Which isotope is used in the nuclear power plants to generate electricity?

• Uranium 235

• Iodine 131

• Cobalt 60

• Uranium 238

What property of an element determines its chemical behaviour?

• Size of an element

• Valency of an element

• Molar mass of the element

• (d) None of these

Which of the following does not match the characteristics of an Isotope?

• Isotopes of some elements are radioactive

• Isotopes are the atoms of different elements

• Isotopes differ in number of neutrons

• Isotopes have similar chemical properties

Which of the following elements does not exhibit the electrovalencey?

• Sodium

• Calcium

• Carbon

• Chlorine

Which scientist gave the concept of fixed energy levels around the nucleus?

• Ernest Rutherford

• Neils Bohar

• J.J.Thomsan

• None of these

What prevents an atom from being collapsed?

• The nuclear forces

• Movement of electrons in discrete energy levels

• The electron-electron repulsions

• All of these