# 19.1 Occurrence, preparation, and properties of transition metals  (Page 9/27)

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$\text{CoO}\left(s\right)+{\text{2HNO}}_{3}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{Co}{\left({\text{NO}}_{3}\right)}_{2}\left(aq\right)+{\text{H}}_{2}\text{O}\left(l\right)$
${\text{Sc}}_{2}{\text{O}}_{3}\left(s\right)+\text{6HCl}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{2ScCl}}_{3}\left(aq\right)+{\text{3H}}_{2}\text{O}\left(l\right)$

The oxides of metals with oxidation states of 4+ are amphoteric, and most are not soluble in either acids or bases. Vanadium(V) oxide, chromium(VI) oxide, and manganese(VII) oxide are acidic. They react with solutions of hydroxides to form salts of the oxyanions ${\text{VO}}_{4}{}^{3-},$ ${\text{CrO}}_{4}{}^{2-},$ and ${\text{MnO}}_{4}{}^{-}.$ For example, the complete ionic equation for the reaction of chromium(VI) oxide with a strong base is given by:

${\text{CrO}}_{3}\left(s\right)+{\text{2Na}}^{\text{+}}\left(aq\right)+{\text{2OH}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{2Na}}^{\text{+}}\left(aq\right)+{\text{CrO}}_{4}{}^{2-}\left(aq\right)+{\text{H}}_{2}\text{O}\left(l\right)$

Chromium(VI) oxide and manganese(VII) oxide react with water to form the acids H 2 CrO 4 and HMnO 4 , respectively.

## Hydroxides

When a soluble hydroxide is added to an aqueous solution of a salt of a transition metal of the first transition series, a gelatinous precipitate forms. For example, adding a solution of sodium hydroxide to a solution of cobalt sulfate produces a gelatinous pink or blue precipitate of cobalt(II) hydroxide. The net ionic equation is:

${\text{Co}}^{2+}\left(aq\right)+{\text{2OH}}^{\text{−}}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}\text{Co}{\left(\text{OH}\right)}_{2}\left(s\right)$

In this and many other cases, these precipitates are hydroxides containing the transition metal ion, hydroxide ions, and water coordinated to the transition metal. In other cases, the precipitates are hydrated oxides composed of the metal ion, oxide ions, and water of hydration:

${\text{4Fe}}^{3+}\left(aq\right)+{\text{6OH}}^{\text{−}}\left(aq\right)+\text{n}\phantom{\rule{0.2em}{0ex}}{\text{H}}_{2}\text{O}\left(l\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}2{\text{Fe}}_{2}{\text{O}}_{3}\text{·}\left(\text{n}+3\right){\text{H}}_{2}\text{O}\left(s\right)$

These substances do not contain hydroxide ions. However, both the hydroxides and the hydrated oxides react with acids to form salts and water. When precipitating a metal from solution, it is necessary to avoid an excess of hydroxide ion, as this may lead to complex ion formation as discussed later in this chapter. The precipitated metal hydroxides can be separated for further processing or for waste disposal.

## Carbonates

Many of the elements of the first transition series form insoluble carbonates. It is possible to prepare these carbonates by the addition of a soluble carbonate salt to a solution of a transition metal salt. For example, nickel carbonate can be prepared from solutions of nickel nitrate and sodium carbonate according to the following net ionic equation:

${\text{Ni}}^{2+}\left(aq\right)+{\text{CO}}_{3}{}^{2-}\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}{\text{NiCO}}_{3}\left(s\right)$

The reactions of the transition metal carbonates are similar to those of the active metal carbonates. They react with acids to form metals salts, carbon dioxide, and water. Upon heating, they decompose, forming the transition metal oxides.

## Other salts

In many respects, the chemical behavior of the elements of the first transition series is very similar to that of the main group metals. In particular, the same types of reactions that are used to prepare salts of the main group metals can be used to prepare simple ionic salts of these elements.

A variety of salts can be prepared from metals that are more active than hydrogen by reaction with the corresponding acids: Scandium metal reacts with hydrobromic acid to form a solution of scandium bromide:

$\text{2Sc}\left(s\right)+\text{6HBr}\left(aq\right)\phantom{\rule{0.2em}{0ex}}⟶\phantom{\rule{0.2em}{0ex}}2{\text{ScBr}}_{3}\left(aq\right)+{\text{3H}}_{2}\left(g\right)$

The common compounds that we have just discussed can also be used to prepare salts. The reactions involved include the reactions of oxides, hydroxides, or carbonates with acids. For example:

what is electricity
electricity refers to the flow electrons
John
Hi. please can you tell me more on chemical equation
When 1 or 2 chemicals react, they rearrange their atomic composition forming new compounds. The total mass before and after is the same/ constant. Chemical equations of same reactants react in same ratios e.g. 1 Na ion reacts with 1 water molecule or a multipier like 1 mole of Na ions react with 1
Abdelkarim
Mole of water molecules. In that example we multipied by 6.02*10^23 or avogadro constant (L). Or 2 Na+ ions with two water molecules. The arrow means '' to form '' Some times conditions or reactants are written above the arrow like H+ or enzyme or temper, sometimes physical states are written
Abdelkarim
Beside the chemical Aqueous (aq) which means solute dissolved on water. Solid (s) etc Some chemical equations are written next to it ΔH= # which means enthalpy change which describes if the reaction is endothermic (+) or exothermic (-).
Abdelkarim
Some are reversible and have half double arrow sign.
Abdelkarim
what is the meaning of atoma
what is theory
what is chemical compound
Lorrita
A compound is the result of chemical bonding between 2 or more different elements.
Abdelkarim
difference between Amine and amide
what is the difference between alkanal and alkanone
difference between alkanol and alkanal
Michael
whaatt
Saturday
you are not well at all
Ibrahim
is organic compounds used for drying agent
Sulfuric acid is used as a drying agent.
Abdelkarim
what is an atom
An atom is the smallest part of an element, for instance gold atoms are the smallest part of gold that can enter a reaction. An atom must consist protons and electrons of equal number. You can think of those subatomic particles as spheres, but not orbiting randomly they move in specific way in
Abdelkarim
That was partially described mathematically. As a muslim, we believe that god created all matter from nothing. He is the Able, and only who can create matter in the begging in the big bang that was described in the Quran in chapter 17 verse 30, 1400 years ago, you can read it from internet.
Abdelkarim
what is electron affinity
John
do you have a private jet
Ibrahim
what is acid
Proton donor (H+). Like in lemons, oranges and some medicines.
Abdelkarim
what is titration? and how can i get my readings?
what is electrolysis?
what is the formula you use when calculating for gas law?
favor
PV=nrt
Farid
electro-means electricity while lysis-means splitting up so electrolysis simply means splitting up by means of electric current
John
good day. how may I see previous question asked in this chat, please?
Asha
Asha, A person named Favor asked what is meant by the term electrolysis
John
what is a sample
According to google, a speciemen taken for specific testing or analysis.
Abdelkarim
how would you carry out a qualitative analysis for two samples of salt suspected to contain chloride ion, bromide ion,iodide ion and carbonate ion
You can search google for test for these ions or test for anions ingeneral which will help you as it contauns videos too.
Abdelkarim
what is acid
Olubodun
why don't you just search for what is acid
Ibrahim
This is a question you're being tested Abdelkarim stop being rude
John
an element x with electronic configurations as 2s²,2p²,3p6,combines with another element y with electronic configuration as 1s², 2p²,3p²,3p5,derive the chemical formula of the compound
These electrongic configuration are entered wrong, any way, you can use an app called peridoic table 2021 that has advabced electric configuration in your studying. Use it to learn about patterns easier. And use it to solve problem: identify elements, then figure out bonding and ration for example:
Abdelkarim
The elemtents are H and S Then the formula is H2S.
Abdelkarim
an element x with electronic configurations as 2s²,2p²,3p6,combines with another element y with electronic configuration as 1s², 2p²,3p²,3p5,derive the chemical formula of the compound
what is atomic number
Dorcas
It is the number of protons in the nucleus of an atom, which is unique for each element e.g only gold atoms have 79 protons in their nucleus.
Abdelkarim
hmm
favor
the number present in proton in nucleus of an atom
favor