1. Vocabulary Atomic Structure

2. anion ___ are negatively charged ions - atoms that take electrons.

3. atomic number ____ is equal to the number of protons in an atom; used to arrange the periodic table.

4. Aufbau Principle The _____ tells us that electrons fill the energy levels from the nucleus out.

5. average atomic mass By taking the weighted percentage of all naturally occurring isotopes of an element, we can calculate the ____, which is the mass found on the periodic table.

6. Bohr's Atomic Model ____ of an atom is a simplified visual representation of invisible atomic structures, where the nucleus is surrounded by layers of electron shells that allow us to visualize something that is too small to be seen.

7. cation ____ are positively charged ions - atoms that give away electrons.

8. charge Atoms that give or take electrons and become ions are said to have a positive or negative ____, which causes them to attract or repel other particles that have a ____similar to a magnet (same word in both blanks).

9. Dalton's Postulates In the early 1800's, ___ were published, which gave us a strong definition for nuclear theory, much of which is upheld today.

10. electron ___ are subatomic particles with a negative charge, no mass value, and are located outside the nucleus of the atom; responsible for chemical reactions.

11. electron cloud The area of an atom that holds the electrons is called the ___, which is divided into levels and sublevels called orbitals.

12. electron configuration ____ is a representation of how the electrons are grouped or stacked around the nucleus of an atom. It can be drawn out in picture form (orbital diagram) using arrows, or in a shorter version, only naming the sublevels and the number of electrons present in each.

13. electron shell An orbital or sublevel is sometimes called an ____, with the very outer one being called the valence shell.

14. energy ___ is the ability or capacity to do work or to produce change. Forms include heat, light, sound, electricity, and chemical energy.

15. energy levels For electron configuration, the electron shells are grouped into ___.

16. Hund's Rule _______ demonstrates that electrons must fill the energy levels / orbitals evenly - they will spread out before they share in a level.

17. hyphen notation ___ gives the name of the element and the number of the atomic mass separated by a hyphen - such as carbon-12.

18. ions ____ are the result of gaining or losing electrons by atoms.

19. isotopes Atoms have different numbers of neutrons in their nuclei, which are said to be ____ because their masses will vary.

20. Lewis Dot Diagram A ___ is used to depict how many valence electrons surround a given atom by using the nuclear symbol surrounded by the proper number of dots.

21. mass number ___ is equal to protons plus neutrons; it is the average atomic mass rounded to a whole number.

22. neutron A ___ is a subatomic particle with no charge, mass is about 1, and is located in the nucleus of an atom.

23. nuclear symbol The letter or letters that represent an element are called the _____, which can include details about the structure or parts of that atom.

24. octet rule The _____ tells us that all atoms want to have 8 electrons in their valence shell, with H as an exception. (Remember that all atoms can only hold 2 electrons in the very first energy level, which is the only completely stable exception to this rule)

25. orbital The exact 'mini highway' that electrons fly around on is called an ___.

26. orbital diagram When showing the how the electrons are grouped or stacked around the nucleus of an atom, It can be drawn out in picture form called an _____ using arrows, or in a shorter version, only naming the sublevels and the number of electrons present in each.

27. Pauli Exclusion Principle The ______ states that there can only be 2 or less electrons in each orbital of each energy level and they must have opposite spins.

28. proton A subatomic particle with a positive charge is called a ____, has mass of about 1, and is located in the nucleus of the atom.

29. Rutherford's Atomic Model ____ of the atom describes it as a small, heavy nucleus surrounded by orbital electrons; this was the basis for other scientists who completed the model to represent atoms in the way they are understood to exist still today.

30. Schrodinger & quantum mechanic model ___ attempt to explain the structure of an atom and electron configuration by using the laws of probability to predict the location of electrons.

31. subatomic particles The parts that make up an atom are called ____ - protons, neutrons and electrons.

32. sublevels When describing electron configuration, remember that each level is broken down into ____, called s, p, d and f, each with a specific number of orbitals.

33. Thomson's Experiments In ____, he used a cathode ray to determine charges and locations of subatomic particles. His theory (called the 'plum pudding model’) was later disproved, but did serve as a strong catalyst for the work of others.

34. valence The outer energy level of an atom is called the ____ shell and the electrons that are in it are called ____ electrons. (same word for both blanks).