Which element forms an ionic compound when it reacts with lithium

Fluorine

Explanation:

Flourine forms an ionic bond when combined with lithium. The valence electronic shell of lithium has just one single electron. Fluorine has 7 electrons in its valence shell but requires just a single electron to complete its octet. When lithium and fluorine combines, fluorine achieves its octet and lithium resembles Helium, a noble gas. This transfer of electron between Li and F is what results in an ionic bond between the two elements. It is also worthy to note that for an ionic bond to form, the electronegative difference between the two atoms should be greater than 0.7.

Fluorine has an electronegativity of 4.0 and that of Li is 1.0. The difference is 3.0. This implies that an ionic compound would be formed. The compound is LiF, Lithium Fluoride.

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.