(2)CO has an electron number of 14, and contains two atoms, and its isoelectrodes are CN- and C22-; N atoms in NH3 form four δ bonds, which are hybrid sp3；; Ammonia gas is easy to liquefy, which absorbs a lot of heat and can be used as refrigerant. In the structure of [Ni(CO)2(NH3)4]2+, CO can be located in two adjacent and opposite positions on the plane.

So the answer is: CN-, C22-; Sp3 liquid ammonia needs to absorb a lot of heat when vaporizing; 2;

(3) The electronic arrangement formula of Ni3+is [Ar]3d7 or 1s 22 p 63s 23 p 63d 7, NiO(OH) is oxidizing and reacts with hydrochloric acid, and the chemical equation is 2NiO(OH)+6HCl (concentrated) =2NiCl2+Cl2↑+4H2O.

So the answer is: [Ar]3d7 or1s222p63s23p63d7; ; 2NiO(OH)+6HCl (concentrated) = 2nicl2+Cl2 ↑+4h2o;

(4) According to the battery structure, Ni is located on the battery surface, and there are 10 Ni in * *, so the average value of Ni is 10× 12 = 5, and the anode of the primary battery undergoes oxidation reaction. According to the total reaction formula of the primary battery, the negative reaction formula is Lani5H6+6OH-6E-λ.

So the answer is: 5; ? LaNi5H6+6OH - 6e-═LaNi5+6H2O.