give reasons for the following
Answers
Answer:
Explanation:
1. Isotopes of a given element have identical chemical properties but slightly different physical properties and very different half-lives.
2. Number of neutrons in an atom. Now, mass of protons and neutrons is measured in daltons or atomic mass unit,u but the mass of each neutron and proton is slightly greater than 1 dalton, so actual atomic mass is slightly greater than mass number.
3. Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. Electrons are tiny, negatively charged particles in an atom that move around the positive nucleus at the center
4. Helium is one of noble gases in group 8 of the Periodic Table. All these have a full outer electron shell. The proton number of helium is two, so a helium atom has two electrons, which exist in the 1s shell. It doesn't to gain or lose electrons to fill thus shell and is unreactive.
Answer:
please mark as brainlist I say 1 and 4
