La puresa del cangrejo.

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17. for each one of the following pairs, indicate what species is more big. Explain your reasoning in terms of the structure electronic of each species.

(a) Li+ or F- F

b) Ca2+ ó Ca CA2+

18. for each of the following pairs, indicate what is smaller.

(a) Cl or Cl-

(c) Al3 + or Na+

19. explain what are the rules of the "Duet" and "byte"

Dueto: In the case of the atoms of the elements H, Li and Be, when they establish bonds, they tend to complete their last energy level with 2 electrons and reach the electron configuration of noble helium gas (He). (Duet Rule)

-Metallic elements give up electrons.

-Non-metallic elements gain or share electrons.

Octeto: The term "octet rule" came about because of the established number of electrons for the stability of an element, that is, the atom is stable when it has 8 electrons in its valence layer.

To achieve such stability suggested by the octet rule, each element must gain or lose electrons in the chemical bonds, so that they acquire eight electrons in the valence layer.

20 how many electrons are involved when two atoms in a molecule are connected through a "double bond"?

2 electrons

21 what it means when two atoms in a molecule are connected by means of a "triple bond"?

When the covalent bond is formed by three pairs of electrons only, it is called triple bond

An example of this is the nitrogen molecule: N ≡ N (N 2).

The symbol "≡" is used to represent the three pairs of shared electrons.

22 enter the structure of Lewis easily for each of the following atoms.

(a) Mg (Z = 12) b) S (Z = 16) c) Br (Z = 35)

[pic 10] [pic 11] [pic 12]

23.- write a structure of Lewis for each of the following simple molecules. Shows all the pairs of electrons of valence of link lines and all pairs of electrons from valencia's not link points.

(a) NBr3

[pic 13][pic 14][pic 15][pic 16][pic 17][pic 18][pic 19][pic 20]

Br N Br[pic 21][pic 22][pic 23][pic 24][pic 25][pic 26][pic 27]

[pic 28][pic 29][pic 30][pic 31]

Br[pic 32][pic 33][pic 34][pic 35]

(b) CBr4 [pic 36]

24. What is the structure geometry of the molecule of the water? Draw a representation

[pic 37]

25. What is the structure geometry of the molecule of the ammonia? Draw a representation of the molecule indicating the angle approximately between their links.

[pic 38]

ammonia

Many pairs of electrons of valencia surround the atom of nitrogen in the NH3?

4 pairs

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