(1) Iron is the 26th element. There are 26 electrons outside the iron core, and the iron atom loses two electrons and becomes Fe2+. According to the structural principle, the electron arrangement outside the ion nucleus is 1s 22 p 63s 23 p 63d 6? Or [ar] 3d6;

Green water purifier K2FeO4 can be prepared by mixing Fe2O3, KNO3 and KOH, heating and melting, in which KNO3 is reduced to KNO2, and KNO2 and H2O are also generated. The chemical equation obtained by equilibrium is Fe2O3+3KNO3+4KOH? High temperature? . ? 2k 2 FeO 4+3k NO2+2H2O；

So the answer is: Fe2O3+3KNO3+4KOH? High temperature? . ? 2k 2 FeO 4+3k NO2+2H2O；

(2)[Cr(H2O)4Cl2]Cl？ In 2H2O, Cr forms coordination bonds with 4 H2O and 2 Cl-, so the coordination number is 6. There are peroxy bonds, Cr-O bonds and Cr=O in CrO5, and Cr is+1 in the four Cr-O bonds and +2 in the Cr=O bond, so the structural formula is;

So the answer is: 6; ;

(3)Ni(CO)4 is a liquid volatile substance, so it has a low melting point, so it is a molecular crystal;

The valence electron number of Ni is 10, and each ligand provides an electron pair, so 10+2n= 18, so n=4.

If the number of atoms and valence electrons in an isoelectronic body are the same, then the number of atoms of CN-, N2 and CO is 2 and the number of valence electrons is 10, then they are isoelectronic bodies.

So the answer is: molecular crystals; 4; CN-；

(4) At room temperature, the gaseous hydride formed by carbon and hydrogen with the carbon number ratio of 1: 1 is acetylene (C2H2), and the molecule contains two single bonds and 1 triple bonds, so the molecule contains 3 1 σ bonds, two п bonds, σ bonds and п bonds. In acetylene molecules, the sp 1 hybrid orbital of carbon atoms forms a valence bond with the 1s orbital of hydrogen atoms;

So, answer 3: 2; Sp 1 hybrid orbitals of carbon atoms and 1s orbitals of hydrogen atoms;

(5) The cell contains four H atoms, and the number of copper atoms is = 18×8+6× 12=4, so the sum of the masses of four hydrogen atoms and four copper atoms is 64.5+ 1NA. Let the cell side length be a and the cell volume be a3, then the density ρ = MV = 65. A×4a3=d, then a = 3mna× 4d = 3260dna;

So the answer is: 3260dNA was praised and trampled. What is your evaluation of this answer? Put away comments//high quality or satisfaction or special types or recommended answers dottimewindow.iperformance & window.iperformance.mark ('c _ best',+newdate); Lawyer recommendation service: If your problem has not been solved, please describe your problem in detail and consult other similar problems for free through Baidu Legal Professional Edition. 20 14- 12-22 stainless steel is increasingly favored by people for its excellent corrosion resistance. Stainless steel is mainly an alloy composed of iron, chromium, nickel, copper, carbon and other elements. Ⅰ More similar questions? & gt recommended for you: F.context('cmsRight', [{'URL':'/d01373f082025aaf511aa256e9edab64034f1a07? x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId':'A24KA00562 '，}，{ ' URL ':/s？ word = % E6 % AC % A7 % E6 % B4 % B2 % E6 % 9D % AF & sa = searchpromo _ ozb _ zhidao _ tuijian '，' src ':'/3 BF 33 a 87 e 950352 AAF 5 df 4954 143 fbf2b 2 1 18 b6b？ x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto '，' contractId ':' '，}])； The price of electric cars has dropped many times. Is the quality guaranteed? What impact will the "network toilet" have? Is Huaqiang North's second-hand mobile phone reliable? Why is the cost of cancer treatment getting higher and higher? I recommend f.context ('recbrand', [{"img": "\/86D6277F9E2F07083523F69DFB 24B 899A901F20d? x-BCE-process = image % 2f resize % 2Cm _ lfit % 2Cw _ 450% 2Ch _ 600% 2c limit _ 1% 2f quality % 2Cq _ 85% 2f format % 2Cf _ auto "，" url":"/hm.js？ 6859 ce 5a af 00 FB 00387 e 6434 E4 FCC 925 "； var s = document . getelementsbytagname(" script ")[0]； s.parentNode.insertBefore(hm，s)； })(); window . TT = 1720 130059；