1. Periodic Trends Compiled by R. Erwin Rockwall ISD

2. Periodic Table • The Periodic Table of the Elements we use today is credited to Dimitri Mendeleev. • It is arranged in Columns and Rows • Columns are called “Groups” or “Families” • Rows are Called “Periods” • The Periodic Table reflects all of the known elements. • Useful in predicting: • Chemical properties of the elements • Trends • Behavior of elements + +Some information from Cscope

3. Periodic Table - Groups • Groups (or “Families”) – Vertical (Y-axis) columns of elements • Numbered from 1 – 18 • Elements in a group are most similar in behavior and properties. • Behave alike because all elements in a group have the same number of valence electrons. • Radius of atom increases as go down the column • As add more energy rings http://www.tutorvista.com/content/science/science-ii/periodic-classification-elements/trends

4. Periodic Table - Periods • Periods – Horizontal (X-axis) rows of elements • Atomic Numbers increase in increments of 1 proton from left to right • +1 so Atomic Number increases by +1 • Atomic mass also increases • All elements in the same period have the same number of energy rings. http://www.tutorvista.com/content/science/science-ii/periodic-classification-elements/trends.php#number-of-shells-in-a-group-increase

5. Table Trends-Overview • Radius – distance from the center of the nucleus to the outer most shell of an atom • Radius of atoms Decrease from left to right • Due to increasingly tighter bonds as add protons • Ionization Energy –the amount of energy needed to rip an electron away from an atom • Electronegativity – The ability to form compounds. • Electron Affinity – the energy change when an electron is added to a gaseous neutral atom • Metallic Properties – Element’s ability to conduct energy

6. Table Trends- Radius • Radius – distance from the center of the nucleus to the outer most shell of an atom • Radius of atoms Decrease from left to right • Due to increasingly tighter bonds as add protons • Radius of atoms Increase as you go down the column • Due to adding of energy levels

7. Table Trends-Radius Small Radius Small Radius • Radius size works like this: Larger Radius LargestRadius

8. Table Trends-Radius • Or this

9. Table Trends- Ionization Energy • Ionization Energy – the amount of energy required to rip an electron away from an atom. • Harder going right across a period • Easier going down a group

10. Table Trends-Electron Affinity • Electron Affinity – the energy change when an electron is added to a neutral atom • Affinity (change) is greatest gong right across a period, and up a group. • Greatest in upper right sections (Noble gasses) • Largest changes up and to right

11. Table Trends-Electronegativity • Electronegativity– the ability to attract and gain electrons to form compounds • Increases gong right across a period and up a group. • Greatest in upper right sections EXCEPT for Noble Gasses • Decreases gong left across a period and down a group. • Least in lower left metals in greater periods • Due to increasing distance from nucleus http://chemwiki.ucdavis.edu/Inorganic_Chemistry/Descriptive_Chemistry/Periodic_Table_of_the_Elements/Periodic_Trends#Periodic_Trends_for_Electronegativity

12. Table Trends-Electronegativity • Electronegativity– the ability to attract and gain electrons to form compounds

13. Table Trends- Electronic Affinity

14. Table Trends- Metallic Properties • Metallic properties are the relative properties of elements to be good conductors of energy • This can be thermal energy (heat) or • Electrical energy (electricity)

15. Table Trends- Summary • One thing all trends have in common – All are related to the element’s properties, and its Valence Electrons. • We can tell much about an element by its place in the Periodic Table

16. Table Trends-Summary