La puresa del cangrejo.

1.-Define chemical bond

A chemical bond is the physical interaction responsible for the interactions between atoms, molecules and ions, which has a stability in diatomic and polyatomic compounds.

2.-What is the power of link?

Is the energy needed to break one mole of such bonds. 

3 What is it mean when it says that a bond is polar?

The polar covalent chemical bond is the bond between two atoms of different electronegativity that makes the electronic charge density higher than the one of greater electronegativity.

? Provide two examples of molecules with links polar.

Examples:  METHANE CH4, CARBON DIOXIDE CO2

4. what difference in electronegativity are those compounds Ionic?

* Ionic (difference greater than or equal to 1,7)
* Covalent polar (difference between 1.7 and 0.4)
* Covalent non-polar (difference less than 0,4)

5. enclose in a circle the element more electronegative.

(a) Na, H         b) F,Br               c) N, F

6. mark with a cross the less electronegative element.

(a) K, Na         b) F, Br           c) B, F

7. based on the values of electro negativities of Figure 6.3 of your textbook indicate the link waited for each pair. (Covalent Ionic (E.I.), (EC) or polar Covalent (ECP).

(a) si-O = polar Covalent      b) Ba-O _ Covalent Ionic

8 highlight the molecules containing polar Covalent bonds

(a) H2O        b) CO          c) F2           d) N2

9. based on the values of the electronegativity of Figure 6.3 of its textbook point to what is the most polar link in each of the following pairs?

(a) H-F or H-Cl

(b) O-Cl or O-Br

10. What is called a dipole moment?

The dipole moment is a quantitative measure of the polarity of a molecule. The greater the electron displacement in the molecule, the greater its dipole moment.

[pic 1]11. for each an of the following molecules diatomic, point with an arrow  the end negative in relation to the other end.

(a)      HCl                   b) BrF   [pic 2][pic 3]

12. for each of the links below, draw a figure indicating the direction of the dipole of the link, including which end of the link is positive and what is negative.

[pic 4][pic 5][pic 6][pic 7][pic 8][pic 9]

(a) C-F     b) C- O     c) SI-C

13. those not metals form ions negative when there is not them enough electrons to reach the configuration electronic of the following gas noble.

14. what ion simple would expect that form each one of the following items? What gas noble has a configuration electronic analog to each one of those ions?

a) chlorine, Z = 17  

b) strontium, Z = 38      

c) oxygen, Z = 8

15. why those cations always are more small that the atoms from which is form?

The cations are smaller than the neutral atoms because they have fewer electrons. Therefore the attractive forces that the nucleus exerts are stronger. This implies that there is a greater contraction and that the cation is smaller.

16 why are anions always larger than the atoms from which they are formed?

The anions are larger than the neutral atoms because they have more electrons. This implies a less attractive force exerted by the nucleus on the electrons. Therefore, the contraction is smaller and this implies a larger size

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