What are you talking about? Cl4? Cl4^4-? I've been doing chemistry for over 40 years and I've never come across a chlorine molecule or ion with four, and only four, chlorine atoms in it.
You're not thinking about CCl4 are you? There is no Cl4^4- anion. CCl4 is a molecular compound, held together by covalent bonds.
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Nope. No Cl4 molecules. When one Cl atom bonds with another Cl atom to form a 100 percent covalent single bond, then the resulting molecule will be at a lower energy than the individual atoms.
Bonding isn't about making anything "happy". Atoms can't be "happy". What bonding is all about is energy. A bond forms when the resulting product is lower in energy than the reacting atoms.
I'm confident that after doing the math, you will find that the energy of a hypothetical Cl4 molecule will be greater than the energy of 4 Cl atoms. Therefore, there is no tendency to form Cl4.Answer 2
Yeah Cl4 is not actually capable of happening. This is because a Cl molecule has 17 total electrons, with 7 electrons in it's outer valence shell (the shell that reacts wish other elements). In essence, the Cl molecule is attempting to gain an electron in order to gain equilibrium which will make the molecule stable, which can't happen given 4 Chlorine molecules. Cl2, however, is possible, and is written:
Cl---Cl, (7+7 =14 total electrons) 2 for the bond between the chlorine molecules, and the other 12 as lone pairs surrounding each Cl molecule to form a total of 8 electrons, thus making it happy!