1. Nucleus always contains a neutron.   True   False   2. Isotopes have same atomic weight.   True   False   3. Electrons are present in the nucleus.   True   False   4. The nucleus of an atom has almost the entire weight of the atom and it consists of protons and neutrons.   True   False   5. Atomic weight of an element is the mass of an atom of that element in grams.   True   False   6. An atom consists of a central nucleus containing positively-charged protons and negatively-charged neutrons.   True   False   7. Neutrons are negatively-charged.   True   False