We learn several things about the elements from the Periodic Table of Elements. Valence electrons are a name for how atoms interact when forming chemical bonds. They are not really electrons that are specifically valence electrons. Oxygen is a good example of this. Oxygen is represented with the symbol O and has eight electrons because it has eight protons. The atomic number eight signifies that oxygen is the 8th element in the table.
And element that is neutral and has no charge consists of the same number of protons and electrons, thus oxygen has 8 electrons. Two of the electrons are in the 1s shell and that shell is full and has the maximum capacity. Two more are in the 2s sub shell and now that shell is full. Then the other four go in the 2p sub shell but this one can hold 6, so it is empty of 2 more possible electrons.
When forming ionic bonds, some atoms give electrons (+ valence) and some receive them (- valence). Oxygen can give up a maximum of 6 electrons from its outer shell but it does not usually do that because of energy level considerations that involves quantum mechanics. It will be easier to add two electrons, that will also fill its outer (2) shell. So a calcium atom comes along with 2 “extra” electrons in its outer shell. It donates them to the oxygen atom. Now they both are happy and each has eight electrons in their outer shell and they are bounded by electrical charges. The two now are associated with oxygen attract the calcium ion.
An ion is an atom but with more or less electrons than protons. So it has a (+) or (-) charge.
Ordinarily we think of oxygen as ‘short’ 2 valence electrons. But in certain conditions it could have six valence electrons.
The number of neutrons generally varies and from the atomic weight they can be calculated. In the periodic table the atomic weight of oxygen is about 16. The weight of protons and neutrons is about 1, and oxygen has 8 protons in the nucleus, so the number of neutrons can be calculated. If we subtract 8 from 16 (16-8) we will get 8.
So oxygen atom has 8 electrons, 8 protons and 8 neutrons. The number of valence electrons is always same with the group number. As oxygen is in group 6, the number of valence electrons that oxygen has is six.
The combining capacity of an atom of an element to form chemical bond is called its valency.
The valency of an element is equivalent to the number of valence electrons and to the number of electrons required to complete eight electrons in valence shell.
The outermost electron shell of an atom is called valence shell. The electrons present in outermost shell of an atom are called valence electrons.
The valence electron of an atom can take part in a chemical reaction because they have more energy than all the inner electrons.
The valency of oxygen in water is 2 as oxygen shares two electrons with Hydrogen and reaches the inert gas octal electronic configuration.
How to find the number of valence electrons in an element?
Valence electrons are present in the outermost shell and surround an atomic nucleus. Valence electrons are important as they play a significant role in an element’s chemical properties, whether they are electronegative or electropositive in nature or they show the bonds that are formed between two atoms.
What are valence electrons?
Valence electrons are found in the outermost shell of an atom. These chemicals are present or absent during a chemical reaction.
Where are valence electrons located?
Though a chemical bond exists between atoms, the changes in the atomic structure are confined to the electrons in the outermost shell. The chemical bond that is formed maybe ionic, covalent or metallic bond.
A periodic table is needed to find the number of valence electrons of an element and the element’s position within it.
Valence electrons and periodic table
The periodic table is a tabular array of the chemical elements that are organized by atomic number, hydrogen to the element with the highest atomic number, organesson.
There are four classifications of elements. They are group elements, transition elements, lanthanides and actinides. Lanthanides and actinides are also called inner transition elements.
There are 18 columns. The columns are also called groups, rows or periods. Sub table consists of 7 rows above and 2 rows discriminating the rarer elements below. A bridge is created between the transition element in groups 2 and 13.
How to find valence electrons?
Even the number of shell increases, the valence electrons remains same as we move down a group.