(1)Cu element is No.29, and there are 29 electrons outside the nucleus, so the arrangement formula of the electrons outside the nucleus is: 1 s22p63s23p63d104s1,so there are1unpaired electrons in the Cu atom, and unpaired electrons in the fourth cycle. The peripheral electronic configuration formula of scandium is 3d 14s2, and the peripheral electronic configuration formula of gallium is 4s24p 1, so in the ground state atoms of all elements in the same period, there are three elements with the same number of unpaired electrons as copper atoms. Cu is element 29, and there are 28 electrons outside the Cu+ nucleus, and its electronic arrangement is 1s 22 p 63s 23 p 63d 10.

So the answer is: 3; 1s 222 p 63s 23 p 63d 10；

(2) In the complex ion [Cu(NH3)4(H2O)2]2+, there is a coordination bond between N and Cu, and the N-H and O-H bonds are polar bonds; The more nonmetallic an element is, the more electronegative it is. If nonmetal: O>N>H, electronegativity O > N > H, the order of N and O is O > N > H,

Therefore, the answer is: coordination bond, polar valence bond; o > N > H；

(3) According to the picture of EDTA structure, it can be seen that carbon atoms exist in the form of single bond and double bond, the valence electron logarithm of carbon atoms is 4 when carbon atoms exist in the form of single bond, and the hybridization mode is sp3, and the valence electron logarithm of carbon atoms is 3 when carbon atoms exist in the form of double bond, and the hybridization mode is sp2.

So the answer is: sp3, sp2；;

(4) From the unit cell of CuCl, it can be judged that the distance between each copper atom and four Cl is the closest and equal, that is, the coordination number of Cu is 4, and according to the chemical formula, the coordination number of Cl is also 4.

So the answer is: 4.