1. Trends and Similarities
Periodic Table
Trends and Similarities

2. Trends of the Periodic Table: At the conclusion of our time together, you should be able to:
Give a trend across and down the Periodic Table for metallic characteristics, reactivity, atomic radius and ion radius, electron affinity, ionization energy, and electronegativity.
Pick the element with the higher trend above from a list of several elements

3. Trends In The Periodic Table:
Ionization Energy Atomic Radius Electron Affinity Electronegativity, Etc.

4. Periodic Trends
Try to determine the trends by looking at the charts on p. 11.

5. Atomic Radius
½ the distance between the nuclei of two identical atoms that are bonded together.

6. Atomic Radius Trends

7. Atomic Radius Trend Explanation.
Electron-electron repulsion makes radius larger, very weak interactions.
Proton – electron attraction = smaller atom
Energy level, n (distance from the nucleus), as they go higher = larger atom

8. Atomic Radius Trends Top to Bottom Left to Right Increases
(larger size atom)
Decreases
(smaller size atom)

9. Electron Affinity
The energy change that occurs when a neutral atom acquires an electron.
Energy is released from the atom.
Atoms that really want another electron tend to release more energy.

10. Electron Affinity Trends
Top to Bottom
Left to Right
Decreases
(less energy released)
Increases
(more energy released)
Noble Gases = 0

11. Ionization Energy
The energy (effort) required to remove one electron from a neutral atom.

12. Ionization Energy Trends

13. Ionization Energy Trend Explanation
The closer to the nucleus (smaller atomic radius), the harder to take an electron away.
The farther away from the nucleus (larger atomic radius), the easier it is to take an electron away.

14. Ionization Energy Trends
Top to Bottom
Left to Right
Decreases
Increases

15. Electronegativity
A measurement of the ability of an atom in a chemical compound to attract electrons.
(how strongly an atom holds onto its own electrons and how strongly it needs another electron)
Most electronegative element – Fluorine (F)
It is assigned the number 4
All other values are based on this value.

16. Electronegativity Trends

17. Electronegativity Trends
Top to Bottom
Left to Right
Decreases
Increases

18. Negative Ions - Nonmetals
Ionic Radius
Cations lose electrons, therefore they tend to be
Positive Ions - Metals
Anions gain electrons, therefore they tend to be
Negative Ions - Nonmetals

19. Ionic Radius Trends

20. (compared to original atom)
Ionic Radius Trends
Cations
-lost electron(s)
(Metals)
Anions
-gained electron(s)
(Nonmetals)
Smaller
(compared to original atom)
Larger