1. Properties of Atoms and the Periodic Table
Study Guide

2. #1 Which two elements do scientists believe are the building blocks of other elements?
Hydrogen and Helium

3. #2 What changes have been made to the model of the atom since Dalton’s simple model.
positively charged protons and neutrons centrally located in a nucleus, negatively charged particles in a cloud

4. #3 Describe and draw the electron cloud model of the atom.
Electrons are most
likely found in energy
levels around the
nucleus

5. #4 Define quarks.
Small particles that make up protons and neutrons

6. #5 Define mass number. How is it determined?
the sum of the number of protons and the number of neutrons in the nucleus of an atom; add protons and neutrons

7. #6 List the characteristics of protons
1+ charge; in the nucleus; mass of
1 AMU; composed of 3 quarks

8. #7 List the characteristics of electrons
1- charge; in the electron cloud; mass is tiny

9. #8 List the characteristics of neutrons
no charge; in the nucleus; mass of 1 AMU; composed of 3 quarks

10. #9 What do energy levels hold
#9 What do energy levels hold? Is there a maximum number of these particles that each level can hold?
Electrons are held in energy levels.Yes.
level 1 = 2 electrons max
level 2 = 8 electrons max
level 3 = 18 electrons max
level 4 = 32 electrons max

11. #10 What are periods?
Horizontal rows of elements on the periodic table.
-same period, same number of energy levels

12. #11 What are groups?
Vertical columns on the periodic table.
-same group, same number of valence electrons and similar chemical and physical properties

13. #12 Elements in groups 3 through 12 are called the?
Transition metals

14. #13 Define isotopes.
Atoms of the same element with different numbers of neutrons.

15. #14 What does the chemical symbol of an element represent?
One capital letter or a capital letter plus one or two smaller letters representing the name of each element.

16. # 15 What are metalloids? What is another name for a metalloid?
Elements with properties of both metals and nonmetals. Semimetals.

17. #16 What is the periodic table?
A table of the elements arranged by increasing atomic number and by changes in physical and chemical properties.

18. #17 Who organized the first periodic table? How was it organized?
Mendeleev arranged the first table by increasing atomic mass

19. #18 What is the average atomic mass of an element?
the weighted-average mass of all isotopes for an element

20. #19 What are electron dot diagrams?
the symbol of an element and dots representing the electrons in the outermost energy level

21. #20 When is an atom considered to be stable?
When its outer level is completed or full of electrons; most elements are stable with 8 valence electrons

22. #21 Compare the masses of protons, neutrons, and electrons.
Protons and neutrons are about the same, 1 AMU. Electrons are much smaller and do not contribute to the mass of the atom.

23. #22 What is a scaled up model?
Models used to visualize things that are too small to see.
Ex> model of the atom

24. #23 What is a scaled down model?
Models that allow you to observe something too large to see all at once
Ex. Model of the solar system

25. #24 Draw electron dot diagrams for the following elements: Helium, Bromine, Radium, Francium, Radon, Hydrogen, Lead, and Magnesium

26. #25 Where in the atom are electrons found?
Electrons are found around the nucleus in the electron cloud, in energy levels of increasing energy with increasing distance from the nucleus

27. #26 How is the identity of an atom determined?
By its atomic number, or the number of protons.

28. #27 What particles are made of quarks?
Protons and
neutrons

29. The number of protons in an atom
#28 What is atomic number?
The number of protons in an atom

30. #29 Give the period and group number for each of the following elements:
Fluorine 2 17
Oxygen 16
Phosphorus 3 15
Nitrogen
Sulfur
Hydrogen 1

31. #30 Sodium → Na Metal Barium → Ba metal Calcium → Ca metal
What is the chemical symbol for each of the following elements, and classify each as a metal, nonmetal, or metalloid:
Sodium → Na Metal
Barium → Ba metal
Calcium → Ca metal
Lanthanum → La metal
Titanium → Ti metal
Aluminum → Al metal
Arsenic → As metalloid
Astatine →At nonmetal
Argon → Ar nonmetal

32. #31 Fill in the following table:
Name
Mass #
Atomic #
# of protons
# of neutrons
Hydrogen-1 1
Hydrogen-2 2
Hydrogen-3 3

33. #32 Hydrogen-1, Hydrogen-2, and Hydrogen-3 are __________________.
isotopes

34. #33 In a neutral atom, the number of electrons is equal to the number of ______________________. protons

35. #34 As you move from left to right on the periodic table the number of electrons increases. What happens to the number of electrons as you move down a group? Increases as well