1. Unit 2: The Periodic Table
CH1120

2. Structure of the Table
Elements are arranged by increasing atomic number
Remember this number tells us the number of protons in the nucleus
Horizontal rows are called periods
Vertical columns are called groups or families
Elements of the same group have similar properties

3. Structure of the Table
Periodic law states chemical and physical properties of the elements repeat in a regular, periodic pattern when they are arranged according to atomic number

4. Structure of the Table

5. Structure of the Table
Group IA to VIIIA are called main group elements
Group 1B to VIIIB are called transition metals
Two rows below the table are called lanthanides and actinides

6. Structure of the Table Group IA are the alkali metals
Group IIA are the alkaline earth metals
Group VIIA are the halogens
Group VIIIA are the noble gases (old term is inert gases)

7. Structure of the Table
State whether the following are main group elements or transition metals
Calcium
Tungsten
Nitrogen

8. Structure of the Table State what family the following belong to
Bromine
Sodium
Magnesium
Argon

9. Metals and Non-metals
All elements can be classified as metals, non- metals, or metalloids

10. Metals
Shiny luster
Various colors, most are silvery
Solids are malleable (thin sheets) and ductile (wire)
Good conductors of heat and electricity
Most metal oxides are ionic solids that are basic
Tend to form cations in aqueous solution

11. Non-metals Do not have a luster Solids are usually brittle
Various colors
Solids are usually brittle
Some hard some soft
Poor conductors of heat and electricity
Most non-metal oxides are molecular substances that form acidic solutions
Tend to form anions or oxyanions in aqueous solution

12. Metalloids
Have characteristics of both metals and non- metals (semi-metals)
These are found on the “staircase” of the periodic table
The only “staircase” element that is NOT a metalloid is aluminum
B, Si, Ge, As, Sb, Te

13. Metals, Non-metals, Metalloids

14. Metallic Character Metallic character increases (H is exception)
Moving top to bottom
Moving right to left
As metallic character decreases elements move from solid to liquid then to gas
At room temperature the only liquid metal is mercury
At room temperature the only liquid non-metal is bromine

15. Metallic Character

16. Semiconductors Solids with limited conductivity
Two metalloids are semiconductors Si Ge

17. Group IA Alkali Metals Soft metallic solids Silvery, metallic luster
High thermal and electrical conductivity
Low densities and melting points
Highly reactive with water
Create ions with 1+ charge

18. Group IIA Alkaline Earth Metals
Harder than alkali metals
More dense and higher melting points than alkali metals
Less reactive than alkali metals
Create cations with 2+ charge
Heavier elements give off characteristic colors when heated
Fireworks; strontium = red, barium = green

19. Group VIIA Halogens
Melting and boiling points increase with increasing atomic number
At room temperature
Fluorine and chlorine are gases
Bromine is a liquid
Iodine is a solid
Diatomic elements (HOBrFINCl)
Form X- halide ions (gain one electron)

20. Group VIIIA Noble Gases
Previously called inert gases
Mostly gases at room temperature
Completely filled s and p subshells

21. Density Mass per unit volume 𝑑𝑒𝑛𝑠𝑖𝑡𝑦= 𝑚𝑎𝑠𝑠 𝑣𝑜𝑙𝑢𝑚𝑒
𝑑𝑒𝑛𝑠𝑖𝑡𝑦= 𝑚𝑎𝑠𝑠 𝑣𝑜𝑙𝑢𝑚𝑒
Density of atoms increases as you move to the lower left hand corner of the periodic table

22. Electron Configuration
As we said before our electron configurations relate to the location on the periodic table
We can divide the periodic table into s, p, d, and f sections
Noble Gases, remember, always have all of the oribitals full
Configurations end with a full p orbital

23. Electron Configuration

24. Bonding Elements interact to gain, lose, and share electrons
Through these interactions atoms attempt to create stable electron configurations
The electrons that are gained and lost are found in the outer most energy shell
Valence electrons

25. Atomic Radius
Based on the distance separating the nuclei when two atoms are bonded to each other
Half the nucleus to nucleus distance between two bound atoms
Used to measure size of atoms
No defined boundaries
Can only come so close to each other

26. Atomic Radius

27. Ionic Radius Ionic radius depends on:
Charge
Number of electrons
Orbitals in which valence electrons are in
For ions carrying the same charge, ionic radius increases as you move down a family

28. Ionic Radius Cations are usually smaller than their parent atoms
Electrons removed from outer shell
Anions are usually larger than their parent atoms
Electrons added to outer shell

29. Ionic Radius

30. Ionization Energy
Minimum energy required to remove an electron from the ground state of a gaseous atom or ion
First and second ionization energies refer to first and second electrons being removed
I1 < I2 < I3…

31. Ionization Energy

32. Electron Affinity
Energy change that occurs when an electron is added to a gaseous atom or ion
Measures the attraction of the atom for the added electron

33. Electron Affinity

34. Valence Electrons
Remember as we move down a group we are adding a new energy level
We can tell the number of valence electrons in main group elements
Group number = valence electrons