2+

Calcium has 2+ charge as it’s electronic configuration is 2,8,8,2. Therefore it gives 2 electrons to other non-metal which has 6 electrons in its outermost shell. And by doing this it becomes stable. We can conclude that the number of electrons the metal gives and non metal takes is referred to as its charge.

In calcium chloride (CaCl2), there are two Cl- ions for each Ca2+ ion.

2+ charge

The net charge of an ionic compound must be zero. Therefore, the number of cations and anions in an ionic compound must be balanced to make an electrically neutral molecule. When naming ionic compounds, the cation retains the same name as the element.

polar covalent bonds

A partial charge is a non-integer charge value when measured in elementary charge units. Partial charge is more commonly called net atomic charge. It is represented by the Greek lowercase letter δ, namely δ− or δ+. Partial charges are created due to the asymmetric distribution of electrons in chemical bonds.

The bond between H and F atom in HF molecule is a polar covalent bond.

Fluorine is the most electronegative element, and the Lewis structure of HF shows the one H-F bond and three lone pairs.

It has seven electrons in its outer shell and needs only one more to complete the stable octet. Fluorine gas consists of F2 molecules with a single F-F bond between atoms. Its hydrogen compound is hydrogen fluoride, HF, in which the F atom is surrounded by three lone pairs and one bonding pair (see right).

HCl, HBr, and HI are all strong acids, whereas HF is a weak acid.

HF is not a strong acid because fluorine is a very small atom. Although the electronegativity difference in this molecule is larger than for HBr and HI, which are strong acids, the small length of the bond makes for a very strong H-F bond.

Relatively speaking, HNO3 is considered a verystrong acid, because the H+ ion will dissociate more readily in water from the NO3-, which results in a lower pKa (dissociation constant) than HF a weaker acid.

HF is a weak acid because the bond between Hydrogen and Fluorine is so short. It is more difficult for the bond to be broken, so it will not completely dissociate in water.

1. HF(aq) is a very reactive, weak acid. This high attraction of fluorine for most other atoms gives rise to a very strong H—F bond that is not broken when HF dissolves in water. The designation of HF as a weak acid does not mean that it is unreactive, only that it does not ionize completely in water.

HF is corrosive because of its proton; it’s corrosive to bones because of its fluoride. HF corrodes glass and HCl doesn’t because silicon tetrafluoride is a more stable complex than the highly reactive silicon tetrachloride. It has little to do with whether the acid is weak or strong.

HCl is a stronger acid than HF because fluorine is more electronegative than chlorine.

Stability of exothermic compound is more than that of endothermic compound, therefore greater the liberated energy greater is the stability. Hence, HF is more stable than HCl.

Hydrogen bonds

HF is the weakest acid because of it’s strong H-F bond. Fluorine being small in size overlaps better with 1s orbital of hydrogen leading to a strong bond. Hence can not give proton easily. Here bond strength overweighs the electronegativity of F .

Now if we compare the bond strength between HI and HCl we find that the HI bond is weaker as Iodine is much larger than chlorine and cannot form an effective overlap between the s orbital of Hydrogen and the p orbital of Iodine, so relatively the H-Cl bond is stronger due to the better overlap of the sigma bonds.

Whereas for homogenous diatomic molecules like F2 and H2, the dipole moments are exactly cancelled out to give rise to a non-polar bond, which makes it non-directional. Which has higher bond strength, HF or H2? So HF has higher bond strength due to high electronegativity difference between H&F.

HF is more ionic(polar) and HI is more covalent. Greater the difference between the electronegativities of the two atoms in the bond, more polar the bond is.

The order of polarity is as follows: HF>HCl>HBr>HI.