Electronic Configuration Of Elements To Verify Place In Periodic Table - Session 1

Cation and Anion Formation. What are cations and anions? Both of these things are actually ions. An ion, is a particle, with unequal number of electrons and protons. Whenever you have that, you have particle with charge called ion. If there are more protons than electrons, the charge is positive. If there are more electrons than protons, the charge is negative.

Cations are ions with positive charges having more protons than electrons. Anions, are ions with negative charges having more electrons than protons. How do you think cations and anions are formed? Metals typically form cations, and non-metals form anions.

Let see the example of Sodium from the left-side of periodic table. It is in Group A. It has one valance electron. First let’s define valence electrons.A valence electron is an electron in the outermost shell. When sodium loses that one valence electron it becomes a cation. So it has one more proton than the number of electrons it has. Therefore it has a positive charge.Let see another example of fluorine for anion. It has seven valence electrons. It needs one more electron to complete its octet. Through the ability to attract electrons, it converts into a fluoride ion having negative charge.

The electrons in the valence shell are called valence electrons. In a period of the periodic table, numbers of valence electrons increases as we move from left-side to right-side. In a group, the number of valence electrons remains constant from top to bottom. Ionization energy is the energy needed to remove an electron from the valence shell of an atom. In a group of the periodic table, the ionization energy decreases from top to bottom. This is because the radius increases. So electrons in valence shell become distant to nucleus. Thus they are easily removed.

In a period of the periodic table, the ionization energy increases from left-side to right-side. This is because the numbers of valence electrons increases and shielding effect increases. Therefore it gets more difficult to remove an electron from the valence shell of the atom.

Elements of Group 1, Group 2 and Group 3 or 13 form cations.Elements of Group 1 include hydrogen, lithium, sodium, potassium, rubidium, cesium and francium.Elements of Group 2 include beryllium, magnesium, calcium, strontium, barium and radium.Elements of Group 3 include boron, aluminum, gallium, indium, thallium and nihonium.Group 1 which has the alkali metals and group 2 which has the alkaline earth metals, are metals which have electrons from valence shell that would detach from them. This results in the same electronic configuration or number of electrons as in preceding noble gases in the periodic table.Group 3 or Group 13 elements have 3 valence electrons and are most likely get rid of them to achieve noble gas electronic configuration. This is why Group 1, 2 and 3 elements form cations.

Elements of Group 5 or 15, 6 or 16 and 7 or 17 form anions. Elements of Group 15 include nitrogen, phosphorus, arsenic, antimony, bismuth, and moscovium.Elements of Group 16 include oxygen, sulfur, selenium, tellurium, polonium and livermorium.Elements of Group 17 include fluorine, chlorine, bromine, iodine, astatine, and tennessine.These group element are non-metals and add 3, 2 or 1 electrons to their outer most shell to complete the electronic configuration to be same as a noble gas.Group 15 elements need 3 electrons to complete valance shell and by adding 3 electrons form tri-negative anion.

Group 16 elements need 2 electrons in valence shell to complete the Valence Shell. By completing the valence shell, they form ⁻² anions.Group 17 elements have 7 electrons in valence shell and need only 1 electron to complete their valence shell. By adding 1 electron they complete the shell and form a negative anion.

Group 4 or 14 elements. The Carbon family has 4 electrons in their outermost shell. Therefore they exactly need 4 electrons to complete their octet. But to gain 4 electrons a lot of energy is required. They form covalent bonds by sharing electrons with one another instead.

Oxidation State.Oxidization state is the number of electrons a particular atom can gain, get rid of, or share with, another atom.It can be applied for any element or compound. It is represented by Arabic numbers, with the charge indicated by negative or positive symbol. It only indicates the electrical charge of atom in a compound. It does not indicate the numbers of bonds that the atom can have. Oxidation state of a pure element is always zero. For example if we take Ca⁺² and O⁻², calcium and oxygen have +2 and -2 oxidation states respectively.

Elemental state.Any atom which is uncombined and has neutral charge with oxidation state of 0 is called elemental state.Pure elements always have zero oxidation state. Copper has a elemental state of 0 as does Iron.The exception is that H₂, O₂, N₂, Cl₂, Br₂, I₂ and F₂ exists as diatomic molecules, in the elemental state having 0 oxidation state.

Oxidation state within a compound.All metals, in compounds, have positive oxidation state.In a compound with non-metals, hydrogen has an oxidation state of +1.In a compound with metals hydrogen has an oxidation state of -1.In a compound, oxidation state can be of 2 or 3 elements. Shown here are some examples of that.

Highest oxidation state of elements.The oxidation state of +8 in Tetroxides of ruthenium, xenon, osmium, iridium, hassium and some complexes of plutonium are examples of highest oxidation state.The lowest known oxidation state is -4. It is seen in some elements of the carbon group.Oxidizing – Reducing Ability.Oxidation is loss of electrons. All those elements which can potentially take electrons from something else to make their ions, are oxidizing agent.Therefore, that oxidizing ability, is the power of that element to oxidize another specie. This means that, elements with oxidizing ability are being reduced.

Reduction, is gain of electrons. Those elements which can potentially give electrons to another specie, are called reducing agents. Therefore, the reducing ability is the power of that element, to reduce another specie. This means, elements with reducing ability, are being oxidized.

As we move, from the left-side to right-side in a period of the periodic table, the oxidizing ability increases. In the left-side elements have strong reducing ability because they are strong reducing agents. In the same manner, in a period, from the left-side to the right-side, the reducing ability decreases.In groups, the behavior or property of reducing, increases from top to bottom. In groups, the oxidizing ability decreases from top to bottom.