A Few introductory Questions about Periodicity

1.  Define ionization energy
Ionization is the physical process of turning molecule or atoms into an ion by removing charged particles, such as electrons or other ions. The energy required to remove an electron from an atom (in its gas state).

2.  Define electronegativity
The property of an atom which causes the attraction of electrons in a bond.  :)


3.  Define electron affinity
 the amount of energy released when an electron is added to a neutral atom or molecule(in its gas phase) to form a negative ion. Most of the time the reaction is exothermic but in order to create an oxide atom, the reaction must be endothermic, or occur inside the atom. 

4.  Differentiate between electron affinity and electronegativity
Electron affinity deals with adding a single electron to an atom. (This is a measured quantity)  Electronegativity relates to the attraction for electrons in a chemical bond.  (This is a derived quantity)

5.  What is the trend within a series in regard to atomic radius?  Why?
As the series increases, the atomic radiuis gets smaller. Why?  because the addition of protons increases the attraction for electrons. Only when the energy level changes does the radius get bigger.

6.  What is the trend within a family in regard to atomic radius?  Why?
Within families, as the atomic number increases, the atomic radius increases as well, since although protons are added, energy levels are added as well. Energy levels contribute a greater difference in atomic radius than the addition of protons.

7.  What is the trend within a series in regard to ionization energy?  Why?
In a series, as proton count (atomic number) increases, the energy required to remove an electron (ionization energy) increases. This is because the atomic radius decreases within a series.

8.  What is the trend within a family in regard to ionization energy?  Why?
As the energy level increases the atomic radius is larger, so the ionization energy is less as the energy level increases, or as you move down the group (family). This happens because because the outer most electron doesn't require much energy to be removed since the inside electrons are shielding the outside electrons.

9.  What is the trend within a series in regard to electronegativity?  Why?
The trend in the series in regard to electronegativity increases when moving from left to right. This is because as the protons increase, the pull on the electrons increases (nuclear charge).

10.  What is the trend within a family in regard to electronegativity?  Why?

as you go down the family, electronegativity goes down.  This is because as it goes down, the energy level increases which means the distance between the electron and the nucleus increases so attraction gets weaker. (inside electrons are repelling).  

11. What is the trend within a series in regard to electron affinity?  Why? 
As the series atomic number increases the amount of energy lost when an electron is added to a neutral atom or molecule to form a negative ion increases.  This is indicated by an increasing negative value.  

12.  What is the trend within a family in regard to electron affinity?  Why?
As the family  atomic number increases the amount of energy lost when an electron is added to a neutral atom or molecule to form a negative ion decreases.
13. Which is larger--K or Na? P or S?
K, and P

14. From which of the following is it harder to remove an electron? Mg or Ba? Fe or Zn?

It is harder to remove to an electron from Mg, because it is closer to the nucleus and therefore is more attracted to the nucleus. Zn is harder to move because it has a smaller atomic radius, meaning the electrons are being held tighter.

15. Which of the following holds a shared pair of electrons the tightest? S or O? Li or Na?
O and Li.  They have the smallest atomic radius.


16. Explain why Cl is smaller than S. (How can it be smaller if it has more stuff in it?)
Cl has more protons, but is in the same energy level as S, thus its atomic radius is smaller.

17. Why is it so difficult to remove an electron from F and so easy to remove one from K? (even though potassium has more protons)
F has a larger ionization energy than K because it has a smaller atomic radius. K has more protons, but also has more energy levels. The addition of energy levels contributes more to the atomic radius than the addition of protons subtract from it.

18. What is the relationship between size and ionization energy?  
As size decreases the electrons are being held more tightly, so ionization energy increases.


19. What is the relationship between size and electronegativity?
The smaller the atom, the greater the electronegativity  See above for reasoning.....

20.  What is the relationship between size and electron affinity?
as size increases, electron affinity decreases because atoms don't hold their electrons as tightly (due to less protons, or more shielding by inside energy levels) the energy released when one is added is less, because there is less pull on the electron from the nucleus.