Can someone explain, in detail, how an ionic bond is formed between Cl2 and Ca?

Question

I have a science exam tomorrow and I would like this question answered. This is the question:

"If a chemical reaction were to occur between Calcium and Chlorine, how many chlorine atoms would join up with Calcium? Explain why."

I don't remember anything about this. I think the valence for Ca is 4, and as for Cl, it's 3, (I think) but can someone explain to me what happens? I know the answer is two. But I can't explain my answer.

Thanks, guys! I fully understand now. Sorry for the mixup between the valences.

Answer 1

The valence of Ca is 2; that of Chlorine is 7, but 6 of the 7 electrons are in lone pairs, so only 1 electron is used for bonding.
You must have the same number of valence electrons for both calcium and chlorine. Since they have different valences, you have to change the number of each species so that the total valence is the same:
2*nCa = 1*nCl
So you need two chlorine (nCl=2) and one calcium atom (nCa=1) to for CaCl2.
2*1 = 1*2

Answer 2

The most stable configuration of valence electrons is a complete octet; or 8 electrons in the outer shell. Atoms will try to bond in a way that allows them to each have a complete octet.

From the periodic table, we know Ca has only two electrons. It will either need to gain six more (very difficult!) or give up two electrons from the outer shell and be happy with the complete octet in the next lower shell.

We also know that Cl has seven electrons. It needs to gain only one more to have a complete octet.

Since Ca has two electrons to give up, and Cl needs only one, Ca will bond with two Cl atoms. When calcium gives up its electrons, it will have a positive charge (2+). When chlorine takes an electron, it will have a negative charge (1-). So the Ca ion and Cl ions attract each other and form ionic bonds.

Answer 3

First off, there are 2 valence electrons for Ca and 7 for Cl

But to answer your question....

Remember that an ionic bond means that one atom gives up its electron while another takes it. This is to get the atom closer to an octet (the same electron configuration as the noble gases). Calcium is in Group 2 (the alkaline earth metals) and so needs to lose 2 electrons to have a noble gas electron configuration. Chlorine, on the other hand, is one electron away from this config. and so one chlorine will accept one electron from calcium. You know this because chlorine is in the halogen group on the periodic table, one away from the noble gases. This is why you need two chlorines. Calcium needs to give up two and chlorine can only accept one; therefore, one calcium, two chlorines.

Hopefully this helps.

Answer 4

First, calcium has a +2 valance. Calcium forms most compounds as an ion. In chlorine ionic compounds, chloride ion has a -1 valance. CaCl2 is the formula for the calcium chloride salt. There is no "bond" where electrons are shared between ions. The calcium ion has two electrons less than a calcium atom and the chloride ion has one electron more than a chlorine atom. Each ion has a full outer shell, so the ions are fairly"happy". Rather, the ions line up in a crystal structure such that in a large volume, there are twice as many chloride ions as calcium ions. One possible structure is fused triangular prism array, which would suffice for a M+2A- 2 ion.

Answer 5

In an ionic bond, 2 or more ions share electrons to get an octet in their second ring. The cation (calcium) and anion (chlorine) will bond together as CaCl2. Calcium has 2 more electrons than it needs for a noble gas configuration, so it gives up one electron a piece to each chlorine. The two bond because of electrostatic forces that result from the new electron pairs. They bond because they are more stable together. Hope this helps.

Answer 6

Calcium will lose 2 electrons. Sulfur will benefit those 2 electrons. they are going to be ionically bonded via the electrostatic allure between the beneficial calcium ion and unfavourable sulfur atom.