This problem is composed of three parts:
(a) For the reaction
1/2 O_2 +2H+ +2e− ⇌ H_2O

the standard electrode potential is + 1.23 V. Under standard-state conditions, if the electrode potential is reduced to 1.0 V, will this bias the reaction in the forward or reverse direction?

(b) For the reaction
H_2 ⇌ 2H+ +2e−

the standard electrode potential is 0.0 V. Under standard-state conditions, if the electrode potential is increased to 0.10V, will this bias the reaction in the forward or reverse direction?

(c) Considering your answers to parts (a) and (b), in an H2–O2 fuelcell, if we increase the overall rate of the fuel cell reaction,
H_2 + 1/2 O_2 ⇌ H_2O
which is made up of the half reactions
H_2 ⇌ 2H+ +2e−
1/2 O_2 +2H+ +2e− ⇌ H_2O
what happens to the potential difference (voltage output) for the reaction?

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.

you did not give any options thus this is the best answer i can give to you with this little information you have given

> they are both natural and not man made

> they can be tracked and predicted by the right tools

-love shrooms