Atomic structure

2. The smallest representative particle of an element.
5. A combination of two or more substances in which each substance retains its own chemical identity.
7. The lowest-energy, or most stable state.
8. Anything that occupies space and has mass.
9. The smallest increment of radiant energy that may be absorbed or emitted.
11. An allowed energy state of an electron in the quantum mechanical model of the atom.
12. Elements that are in the same column of the periodic table.
14. A spectrum that contains radiation at only certain specific wavelengths.
16. A measure of the ability of an atom that is bonded to another atom to attract electrons to itself.
17. A substance consisting of atoms of the same atomic number.
19. An estimate of the size of an atom.
20. Members of group 1A in the periodic table.

1. A higher energy state than the ground state.
3. Members of group 7A in the periodic table.
4. A spectrum that contains radiation distributed over all wavelengths.
6. The energy required to remove an electron from a gaseous atom when is in its ground state.
8. The product of the mass, m, and velocity, v, of an object.
10. A positively charged subatomic particle found in the nucleus of an atom.
13. The energy change occurs when an electron is added to a gaseous atom or ion.
15. A situation in which two or more orbitals have the same energy.
18. One or more orbitals with the same set of quantum numbers n and l.