The "valence" of an element is its "combining power". "Combining power" is the old definition of "valence". it refers to the number of other atoms which it can combine with to make a compound. For instance, Na has a combining power of 1, as does chlorine. Therefore, we get one Na and one Cl in a compound, NaCl. From Na2O we can see that oxygen has a combining power, or valence, of 2.
There are two combinations of Fe and Cl, FeCl2 and FeCl3. Therefore, iron must have two valences - two combining powers - 2 and 3. Somewhere in history, the valance was assigned a + or - to correspond to cations and anions, and along with that came the notion that the sum of the valences for a compound is zero.
Valences are NOT charges unless the substance actually exists as an ion. Today, the term "valence" has pretty much gone by the wayside, and we use "oxidation number" instead. "Oxidation number" is the new "valence". In FeCl2 and FeCl3 we say that iron has oxidation numbers of +2 and +3.
So why does iron have two oxidation numbers? That's because there are two stable combinations of Fe and Cl. Reactions occur because the products will be a lower energy than the reactants. If you place Fe metal in a container of Cl2 gas you will get a reaction which forms either FeCl2 or FeCl3 depending upon the relative amounts of the two reactants. Given sufficient Cl2, the reaction will go to FeCl3 since that product is a bit lower in energy than FeCl2.
We can relate the oxidation number (or valence) to the number of electrons available to react (the valence electrons). Sodium forms only NaCl when sodium metal is placed in Cl2 gas since sodium has only 1 valence electron and can form only one stable compound with chlorine.
How to pick which oxidation number (valence) to use? I might ask my students to simply write all the possible formulas for compounds of iron and chlorine, and I would expect to see FeC2 and FeCl3. There is no way to pick one or the other as the products, unless you are also given the conditions of the reaction.
This is why the names of compounds which exhibit multiple oxidation states include a Roman numeral to specify which oxidation state the metal is in. I.e. iron(II) chloride and iron(III) chloride.
Transition elements contain 2 outermost shells incompleted including the valence shell. But when it reacts with other, it shares,gives or accepts elctrons from its inner shells.
Certain elements combine with other atoms, donating, accepting or sharing electrons in different proportions depending on the nature of the reaction. For example, iron combines with oxygen to form ferrous oxide as well as ferric oxide. In the formation of ferrous oxide, iron exhibits a valency of +2, whereas in ferric oxide, it has a valency of +3. This is termed variable valency
Atoms of solid iron would not have lost electrons to any other element. They are shared with the de-localized electron cloud but the oxidation state is 0. That being the case, there would be no charge. It is a free element. (No joke, a free element has no charge.) If iron were to form a compound it would typically lose two or three electrons to the anion.
Group number 1 = Valency 1+group number 2 = valency 2+group number 3 = valency 3+group number 4 = valency 4+ and 4- (some cases) group number 5 = valency 3-group number 6 = valency 2-group number 7 = valency 1-group number 8 = valency 0For the transition elements they will either state Copper (III) Sulphate or it will be like Cu2(SO4)3You can find the valency by the base of sulphate and you know its positive because metals are always positive and are written in the left.Source: I am a GCE O Level Sciences Student (O2)
it does. for example in H2O oxygen has a valency 2 while in hydrogen peroxide H2O2 oxygen exhibits valency 1
Yes, elements with variable valency can be stored in water. However, the reactivity of the element will determine how stable it is in water. Some elements may react with water to form oxides or hydroxides, while others may remain stable. It is important to consider the specific properties of the element in question when storing it in water.
the smallest element is hydrogen of which its valency is one.
Out of the non-metals you listed, nitrogen (N) is the only one that does not exhibit variable valency. Zinc (Zn), copper (Cu), and iron (Fe) can exhibit variable valency in certain compounds.
The valency of manganese can be determined by looking at its electron configuration. Manganese typically forms compounds in which it has a valency of +2, +3, +4, +6, or +7 depending on the specific compound it forms. This valency corresponds to the number of electrons that manganese can lose or gain to achieve a stable electron configuration.
The valency of an element measures its ability to combine with other elements. This valency is determined by the number of electrons in the outer shell of each atom of an element.
Carbon has a valency of 4, while sulfur has a valency of 6.
Transition elements contain 2 outermost shells incompleted including the valence shell. But when it reacts with other, it shares,gives or accepts elctrons from its inner shells.
Variable valencies are the valencies which can change e.g. Fe (iron) can either have the valency of 2 (Fe II) or 3 (Fe III)
Valency (in chemistry) is the number of the valence bonds of a chemical element.
Certain elements combine with other atoms, donating, accepting or sharing electrons in different proportions depending on the nature of the reaction. For example, iron combines with oxygen to form ferrous oxide as well as ferric oxide. In the formation of ferrous oxide, iron exhibits a valency of +2, whereas in ferric oxide, it has a valency of +3. This is termed variable valency
an element which has valency 2
The highest valency element is oxygen, with a valency of 2. The valency of an element represents the number of bonds it can form with other elements. Oxygen typically forms bonds by gaining two electrons to achieve a stable electron configuration.