Valencies of all 118 elements
The electrons present in the outermost shell of an atom are called Valence electrons.
From the Bohr-Bury scheme, we find the outermost shell of an atom can accommodate a maximum of 8 electrons.
Also, the atoms of the elements show little chemical activity if its outermost shell is completely filled. Also can be said that the elements combining capacity or its valency is zero.
In the inert elements, the helium atoms have two electrons in their outermost shell and all other elements have atoms with 8 electrons in the outermost shell.
The combining capacity of atoms of other elements to react or form molecules with atoms of the same or different elements were the attempts to attain a fully filled outmost shell.
An outermost shell that has 8 electrons is said to be octet.
The atoms would attempt or react to achieve an octet in the outermost shell and this process will be done by gaining, losing, or sharing the electrons.
The losing, gaining, or sharing of electrons gives the direct combining capacity of the elements.
Example Sodium/lithium/hydrogen atoms contain one electron each in its outermost shell so as to lose one electron. These elements are said to have a valency of One (1).
Similarly, the valency of Magnesium is 2, as it has 2 electrons in the outermost shell and aluminum is 3 as it has 3 electrons in the outermost shell.
Valency of Metals
Metals have positive valency as they have +1,+2,+3 electrons in their outermost or valance shell.
The metal having valency ‘1’ is potassium its chemical symbol is K . Potassium is an alkali metal and belongs to Group 1 of the periodic table.
Hydrogen its symbol is ‘H‘ has only one valence electron and can form only one bond with an atom that has an incomplete outer shell.
Helium, its symbol is ‘He‘. Helium only has two electrons in its S-orbit. One Orbit can have only two electrons. As a result, its duplet is fulfilled. As a result, it has no tendency to lose or gain electrons. Due to this, its valency is zero.
Lithium, its symbol is ‘Li‘. Lithium Valency is 1. This is because the atomic number of lithium is 3 and electronic configuration = 2,1. Li (Z=3). To attain stability, Lithium needs to lose one electron. Lithium li number of valence electrons is 1.
Beryllium, its symbol is ‘Be‘. Beryllium Valency is 2. Beryllium’s atomic number is 4. Its electronic configuration is 1s² 2s². It has two electrons in its Valence shell and when the valence shell electrons are more than 4. Then the valency = 8-n.
As its valence shell has 2 electrons present for sharing. Two electrons can be easily donated. As a result valency of Beryllium is two.
Valency of boron
Boron has 3 valence electrons and an atomic number of 5. Boron will lose 3 electrons rather than gain 5 electrons. Therefore valency of boron is 3.
Valency of Carbon
Valency of Carbon in 4. The carbon atom contains 4 electronics in its outermost shell. In order to achieve the noble gas configuration, carbon forms four covalent bonds and shares its valence electrons.
Carbon electron configuration will be 1s22s22p2
Valency of Nitrogen
Nitrogen has either 3 or 5 Valence electrons. This is because it can bond in the outer orbitals 2p and 2s.
Valency of Oxygen
The number of electrons in Oxygen is 8.
The electronic configuration of oxygen is 2,6. In order to complete the octet and to become stable, it accepts 2 electrons to achieve 8 electrons in its outermost shell. Therefore the valency of oxygen is 2.
Valency of Fluorine
The electronic configuration of Fluorine is 1s22s22p5 . The atomic number of Fluorine is 9. It has 7 electrons in the outermost shell. As fluorine is part of the halogen family, it easily gains one electron instead of losing seven electrons.
Hence the valency of fluorine is one.
Valency of Neon
Neon valency is 0, this is because it has completely filled the outermost shell as it is a noble gas. As it is an inert gas and its electronic configuration is 1s2,2s2,2p6. All its orbital is full. Due to this Neon is the least reactive and there is no true compound of Neon has been synthesized.
Neon valency is zero because Neon is a noble, inert, and non-reactive gas.
Valency of Sodium
The electronic configuration of sodium is 1s22s22p6 3s1. Sodium is an alkali metal and it has an atomic number of 11. As per the electronic configuration of sodium, it needs to lose 1 electron from the outermost orbit to attain an octet.
Hence the valence of sodium is 1.
Valency of Magnesium
the electronic configuration of Magnesium is 1s22s22p6 3s2. That is the number of electrons is 12. Magnesium has two electrons in the outermost and it loses two electrons to attain the nearest noble gas configuration.
Hence the valency of Magnesium is 2.
Valency of Aluminium
The electronic configuration of 1s22s22p6 3s2 3p1. Aluminium in its valence shell has 3 electrons and it will lose 3 electrons to complete its octet and to attain the nearest noble gas configuration. Therefore valency of Aluminium is 3.
Valency of Silicon
the electronic configuration of silicon is 1s22s22p6 3s2 3p2. Its atomic number is 14. As silicon is a noble gas, it can gain or lose four electrons. but it loses four electrons to attain an octet state.
Valency of Phosphorus
The electronic configuration of Phosphorus is 1s22s22p63s23p3. Phosphorus has two valencies. As it can lose 5 electrons or gain 3 electrons to form an octet.
This is because Phosphorus has 5 valence electrons in its valence shell, it can either lose 5 electrons or gain 3 electrons to attain noble gas configuration. Therefore Phosphorus has a valency of 3 or 5.
Valency of Sulfur
The electronic configuration of Sulfur is 1s22s22p63s23p4. It has 6 electrons in the valence shell. By that sulfur needs 2 electrons to achieve the octet. As a result, the valency of sulfur is 2.
Valency of Chlorine
The electronic configuration of Chlorine is 1s22s22p63s23p5. The atomic number of Chlorine is 17. It has 7 electrons in its valence. It gains one electron to achieve octet, a stable noble gas configuration. As a result valency of Chlorine is 1.
Valency of Argon
The atomic number of argon is 10. Its electronic configuration is (2,8). The atom is stable as the outermost shell is complete, and the outer electron is 8. Also, argon belongs to the group of noble gases and its valance shells are completely filled as they have no tendency to lose or gain electrons. As a result, the valency of Argon is 0.
Valency of Potassium
The electronic configuration of Potassium is 1s22s22p63s23p64s1. Its atomic number is 19. That is 9 electrons in its valence shell. In order to form an octet, it loses one electron. As a result, the valency of Potassium is 1.
Valency of Zn (Zinc)
The atomic number of Zinc is 30. The Valence shell contains 2 electrons. The electronic configuration of Zinc is 1s22s22p63s23p63d104s2. As Zinc has 30 electrons, which is 28 in the first three wheels and 2 in the fourth.
In order to achieve an octet, it has to gain six or otherwise lose two electrons. There, it loses two electrons in the outermost shell and forms a 2+. As a result, Zinc has a Valency of two(2).
Valency of Ga (Gallium)
The Gallium is located in group 13. The electron configuration of ga is 4s, 4p and 3d. The 4s and 4p electrons can be lost in a chemical reaction. But 3d electrons stay. Therefore Gallium has three valence electrons.
Valency of Ruthenium (Ru)
Ruthenium has 8 valence electrons. The total number of electrons in RU is 44. Its atomic number is 44. Its atomic weight is 101.07. Its melting point is 2,250° C (4,082° F). Its boiling point is 3,900° C (7,052° F). Its specific gravity is 12.30 (20° C).
Ruthenium valence is 1,2,3,4,5,6,7,8. Also, its electron configuration is 2-8-18-15-1 or (Kr)4d75s1.
The valency of lead is 2,4. Its atomic number is 82 and its electronic configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p2. Due to the inert pair effect, Pb displays +2 valency.