Few introductory Questions about Periodicity

1.  Define ionization energy
The energy required to remove an electron from an atom in its gas state.

2.  Define electronegativity
the tendency of an atom to attract shared electrons in a chemical bond.  


3.  Define electron affinity
The Electron affinity of a molecule or atom is the energy change when an electron is added to the neutral atom to form a negative ion.
The greater the affinity, the greater the negative energy change.  A negative energy change means energy released. 

4.  Differentiate between electron affinity and electronegativity
Electron affinity deals with adding a single electron to an atom ( in gas phase). (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?
The further along in the series, the smaller the atomic radius. This is because protons pull the electrons tighter.

6.  What is the trend within a family in regard to atomic radius?  Why?
As you go down the periodic table family the atomic radius goes up. Because you keep adding on energy levels, thus increasing the atomic radius. ( inside electrons repel the outer electrons) 


7.  What is the trend within a series in regard to ionization energy?  Why?
Ionization energy trends increases as you move across a series, because the greater number of protons attracts the electrons in the orbitals more strongly.

8.  What is the trend within a family in regard to ionization energy?  Why?
i.e. increases as the size of the atom decreases; as you move upwards in a family, the atoms become smaller, therefore the i.e. increases

9.  What is the trend within a series in regard to electronegativity?  Why?
There is more electronegativity as you move across a series due to increasing number of protons. 

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

Within a family, electronegitivity decreases with increasing atomic number because of increased shielding effect.   



Hello everyone.  I put correct answers to 11 - 20 on the 5th hour page.  Please go there to double check your answers.


11. What is the trend within a series in regard to electron affinity?  Why? 
 As the atomic number increases along a series, electron affinity increases because as proton number increases, so does th pull on the electrons, and highly attracted electrons release more energy when they are pulled in.

12.  What is the trend within a family in regard to electron affinity?  Why?
Electron affinity decreases from top to bottom within a group. This is caused by the increase in atomic radius.

13. Which is larger--K or Na? P or S?
K, 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.


15. Which of the following holds a shared pair of electrons the tightest? S or O? Li or Na?
1. S     O and Li
2. Na


16. Explain why Cl is smaller than S. (How can it be smaller if it has more stuff in it?)
Because Cl has more protons so the protons attract the electrons inside thus making it 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)
Because F has 7 valence electrons, meaning it would gain electrons more easily than losing them, while K only has 1 valence electron, so it would lose electrons more easily. If an atom has less than 4 valence electrons, it tends to lose them, while if it has more than 4, it tends to gain them.    PLEASE LOOK AT THE 5th HOUR ANSWER TO THIS QUESTION.

18. What is the relationship between size and ionization energy?

The smaller the atom, the greater the i.e. 

19. What is the relationship between size and electronegativity?
If the atom is bigger smaller, there is more electoronegavitity.  Unless it has a full outer shell.

20.  What is the relationship between size and electron affinity?
Size increases with electron affinity.   As size increases, electron affinity decreases.