Unit 3 Study Guide –KEY
1. Who is given credit for creation of the Periodic Table?
Dmitri Mendeleev
2. When he was putting the table together, what characteristics did he use to place the elements in order?
Rows - Increasing mass
Columns – Similar properties
3. What is the definition of atomic mass?
Individual Atoms: Number of protons plus number of neutrons.
Elements: Weighted average of the masses of the isotopes.
4. What units do you put on atomic mass?
amu (Atomic Mass Units)
5. Does the atomic number increase or decrease as you move from left to right? How much does it change
from one element to the next?
Increases by 1 for each element as you move from left to right
6. The vertical columns on the Periodic Table are called what?
Groups
7. Why do elements in the same group have similar chemical properties?
Elements in the same group have the same number of valence electrons in their outer shell.
8. The horizontal rows are called what?
Periods
9. What states of matter are represented by the metals at room temperature (solid, liquid, and/or gas)?
Solid and liquid (all but mercury are solids)
10. There are two groups (families) on the Periodic Table that are considered the MOST reactive, what are they
(give name and number)?
Group 1 (IA) – Alkali Metals
Groups 17 (VIIA) – Halogens
11. Using your answer from question 10, how many valence electrons does each of those groups (families)
have?
Group 1 (IA) has 1
Group 17 (VIIA) has 7
12. Na is a very reactive element in Period 3, what other elements in Period 3 would be considered reactive?
Cl (chlorine). Mg (magnesium) would be slightly less reactive.
13. Every element in the Carbon group (Group 14) has how many valence electrons?
4
