When is a Roman numeral most likely needed in the name of an ionic compound

When the metal of the ionic compound has multiple oxidation states.

Explanation:

Nickel (Ni - At No 28) has multiple oxidation states* => −2, −1, 0, +1,[2] +2, +3, +4[3] (a mildly basic oxide)*. When naming compound of nickel on needs to include a roman numeral in parenthesis after the symbol of the element in order to identify which oxidation state is relevant.

examples

Nickel Halide derivatives include

NiCl => nickel(I) chloride

NiCl₂ => nickel(II) chloride

NiCl₃ => nickel (III) chloride

Such is important in that each of the compounds have different physical and chemical properties due to variations in oxidation states of nickel.

https://en.wikipedia.org/wiki/Nickel

I thought this was unanswered; it is true about the multiple oxidation states, Fe [I]. [II], [III] and so on; generally it evokes the idea of The Transition Metals.

Explanation:

when—without warning—something provokes your anger, you may struggle not to succumb to it. since what typically makes you mad is feeling powerless in the face of what seems unfair, your anger is mostly an attempt at a “quick fix” to right the balance. it’s as though you’re raising a fist in protest, proclaiming that you’re not going to capitulate to such injustice.

there are, however, a multitude of problems related to this immediate, push-back reaction of anger. and probably the key one is that almost never does it resolve the issue that gave rise to it. such reactive anger is probably best understood as self-defeating. as david burns, the author of the seminal self- book feeling good, observes: if realistically, acting on your anger is to make any sense, it needs to meet two criteria—which, in almost every case, is frankly impossible. that is, your anger must:

be directed toward a person who has intentionally (and needlessly) behaved in a hurtful way toward you; and

be beneficial or advantageous to you (i.e., assist you in achieving a desired goal).

i think you’ll agree that only rarely can you claim that your anger is both warranted and , whether to yourself or the relationship.

so let me offer you a two-step alternative to abandoning your better judgment and giving in to the temptation of anger—one that should neutralize your anger in seconds. or, when you’re really angry, in minutes.

but keep in mind that you must really want to execute these steps, be sufficiently motivated to perform them. which means overcoming more unconscious resistance than you might ever have imagined. because there are many immediate “advantages” of anger that can interfere with your resolve, i’ll suggest a few of them that might interfere with your employing this powerful method to rid yourself of counter-productive anger.

explanation: