1. The Modern Periodic Table
Chapter 5.2

2. Element Information in the Periodic Table
Most often there are 4 pieces of information for each element listed on the periodic table.

3. Element Information in the Periodic Table
Most often there are 4 pieces of information for each element listed on the periodic table.
Atomic number
(# of protons)

4. Element Information in the Periodic Table
Most often there are 4 pieces of information for each element listed on the periodic table.
Atomic number
Element symbol
(1st capital, 2nd small)

5. Element Information in the Periodic Table
Most often there are 4 pieces of information for each element listed on the periodic table.
Atomic number
Element symbol
Element name

6. Element Information in the Periodic Table
Most often there are 4 pieces of information for each element listed on the periodic table.
Atomic number
Element symbol
Element name
Atomic mass

7. Atomic Mass Atomic mass depends on:
Distribution of an element’s isotopes
Masses of those isotopes.
Isotopes = same element, different masses
Masses different because:
Same # protons
Different # neutrons

8. Atomic Mass Atomic Mass Units 1 Atomic Mass Unit (amu) =
Scientists chose one isotope to serve as a standard.
This isotope is the most abundant one found in nature
Carbon-12 atom: 6 protons and 6 neutrons.
1 Atomic Mass Unit (amu) =
one twelfth the mass of a carbon-12 atom.

9. Most elements are mixtures of 2 or more isotopes.
Atomic mass is weighted average.
Example: Chlorine atomic mass = amu.
Two natural isotopes of chlorine: chlorine-35; chlorine-37
Chlorine-35: 17 protons and 18 neutrons.
Chlorine-37: 17 protons and 20 neutrons.

10. The Periodic Law
Elements in modern periodic table arranged by increasing atomic number (not mass)
(Atomic number = # of protons).
Periodic Law - Pattern of Repeating Properties
Periods - Each row is a period.
Each period is for a different electron shell or energy level

11. All of the Electron Shells

13. The Periodic Law Modern periodic table – stretched out (7 rows)
Shows periods with Lanthanide & Actinide series where they really belong

14. The Periodic Law
Elements are also arranged into vertical columns called Groups (or Families).
Sounds of musical notes
separated by an octave are
related, but they are not identical.
Properties of elements in a Group (column) are related, but not identical.
Groups - Each column is a Group (or Family).
Similar electron configurations
Similar chemical properties

16. Example: Group 8A (or 18) - Noble Gasses with Full Shells
Helium - Atomic #2
Neon - Atomic #10
Argon - Atomic #18

17. The Periodic Law
Periodic Table of the Elements

18. Metals Largest class of elements on the Periodic Table - Metals.
80% of the elements.

19. Physical Properties of Metals
Malleable and ductile (can change shape)
Malleable = compress without breaking
Ductile = stretch without breaking
Good Conductors (thermal & electrical)
Luster (means they are shiny!)

20. Transition Metals
Groups 3 – 12: Form a bridge between elements on the left and right side of the table
Tough, hard, and strong
Less reactive
than standard metals
Have more properties
in common than
elements in other
groups.

21. Metalloids Share characteristics of both metals & non – metals.
Semi – conductors

22. Non-Metals Insulators (poor conductivity)
Living organisms are mostly non-metals. (especially C, N, O, H)
Most of the compounds in your body contain carbon

23. Variations Across a Period
Across a period from left to right, the elements become less metallic and more nonmetallic in their properties.
From left to right across Period 3, there are three metals (Na, Mg, and Al), one metalloid (Si), and four nonmetals (P, S, Cl, and Ar).

24. Variations Across a Period
Sodium reacts violently with water.
Magnesium will not react with water unless the water is hot.
Aluminum does not react with water, but it does react with oxygen.
Silicon is generally unreactive.
Phosphorus and sulfur do not react with water, but they do react with oxygen.
Chlorine is highly reactive.
Argon hardly reacts at all.