1. An element is a substance made up of different kinds of atoms.   True   False   2. Nucleus always contains a neutron.   True   False   3. In a neutral atom, the number of electrons and protons is equal.   True   False   4. The elements are arranged in order of decreasing atomic numbers in a table called the periodic table.   True   False   5. Neutrons are negatively-charged.   True   False   6. Electrons revolve around the nucleus in shells or orbits.   True   False   7. Isotopes differ in the number of neutrons they have in their nucleus.   True   False