1. Isotopes have same atomic number.   True   False   2. Of a proton, neutron and an electron, the electron is the lightest.   True   False   3. One atom of carbon and two atoms of oxygen combine to form a molecule of carbon dioxide [CO2].   True   False   4. Electrons revolve around the nucleus in shells or orbits.   True   False   5. Isotopes differ in the number of neutrons they have in their nucleus.   True   False   6. Hydrogen and oxygen are combined chemically in a fixed proportion of 2:1 in the compound water.   True   False   7. In a neutral atom, the number of electrons and protons is equal.   True   False   FREE PREVIEW: Last 12 Questions not a part of the free preview. Get Premium Membership to view all questions.