1. Atom - smallest part of an element that cannot be divided further, retaining all properties of the
element
2. Proton - positively charged particle found in the the nucleus of an atom, has a mass of 1
3. Neutron- neutrally charged particle found in the nucelus of an atom, has a mass of 1 & no
charge
ADD: ELECTRON- negatively charged particle found outside the nucleus, has a mass of aero
4. Nucleus - positively charged "core" of an atom, contains all the mass of an atom
5. Nucleon - particle found inside tne nucleus: potons & neutrons. (# nucleons =mass)
6. Atomic number- ONLY NUMBER THAT IDENTIFES AN ELEMENT. equal to the number of
protons in the nucleus
7. Atomic mass - sum of protons and neutrons - calculated by a weighted average of all the
naturally occurring isotopes of an element
8. Atomic mass unit- 1/12th the massof a carbon-12 atom. approx 1 gram
9. Mass number-sum of protons and neutrons
10. Nuclear charge - charge in the nucleus, always positive, equal to number of protons
11. Isotope -form of the element having the same atomic number, different atomic mass
- same number of protons different number of neutrons
12. Ion - charged part of an atom, results from the loss or gain of electrons
13. Electron configuration - indicates the exact arrangement of electrons in an atom
14. Valance electron - outermost electrons, located in outermost energy levele
15. Kernel -all electrons EXCEPT the valence electrons
16. Ground state- electron configuration written eactly as shown on periodic table (electrons are filled
in orbitals in order from lowest energy to highest energy)
17. Excited state- electron configuration written "out of order" from periodic table (an electron has
"jumped" to a higher energy state -out of order form the rules)
18. Photon 1 quantum: a backet or burst of energy released as electrons fall from hi energy to lo
energy
19. Quanta - i photon of energy
20. Bright line spectra- spectral lines that identifies the element: "fingerprint of an element"
21. Continuous spectra- spectrum that shows all the wavelengths of light energy (ROYGBIV)
22. Wave mechanical model - current accepted theory of atomic structure, based on quantum
mechanics, the electrons are located outside the nucleus in orbitals
23. Orbital - region of probability of finding an electron