The shielding of electrons gives rise to an effective nuclear charge, , which explains why boron is larger than oxygen. estimate the approximate felt by a valence electron of boron and oxygen, respectively? a. +5 and +8b. +3 and +6c. +5 and +6d. +3 and +8e. +1 and +4

Option b: +3 and +6.

Explanation:

To calculate the of the valence electron of boron and oxygen, we need to use the next equation:

where Z: is the proton number of the atom and s: is the shielding constant

The electronic configuration of the atom of boron and oxygen is the following:

B (Z=5): 1s²2s²2p¹ → number of valence electrons: 3 (2s²2p¹) → number of nonvalence electrons: 2 (1s²)

O (Z= 8): 1s²2s²2p⁴ → number of valence electrons: 6 (2s²2p⁴) → number of nonvalence electrons: 2 (1s²)

Assuming that the shielding constant is approximately equal to the number of the nonvalence electrons, the of the valence electron of boron and oxygen is:

B:  

O:

So, the correct option is b, +3 for the boron and +6 for the oxygen.  

I hope it helps you!  

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.