In periodic table how we find group and period with atomic number
Answers
heyyy!!!!Mate here is ur answer.....
Explanation:
We already know that all the elements in periodic table are arranged serially according to their atomic numbers. There are 18 groups and 7 periods. The elements are arranged in such a way that the elements get categorized according to their properties.
Here we will work with only basic 8 groups (I A,II A,III A,IV A,V A,VI A,VII A and 0) .In the periodic table the first group (except Hydrogen) consists of strong Alkali Metals, the second group consists of Alkaline Earth Metals. The right of the periodic table consists of the non-metallic elements including noble gas and metalloid. The VII A group is also known as the Halogen Family and its elements are known as halogens. All Noble Gases are in the group 0. All these elements are collectively known as Normal Representative Element.
We have to keep certain things in mind (Not applicable for transition groups and its elements)
1. The period of element relates the number of shells of an atom of the given element.
2. The group is similar to the no of valence electrons of given element.
3. The valency is the no of electrons it accepts or donates. So in case of non-metals valency = 8-valence electrons & in case of metals valency=valence electrons... This is B’COZ non-metals accept so lacked electrons only considered.
4. The number of element in each period is calculated by 2n2.
Steps to find the position of an non-transitional element in periodic table
1. First take the Atomic number of the given element. Say Cl... Atomic no. 17
2. Then calculate the electronic configuration using the atomic number 2+8+7=17 therefore the electronic configuration will be 2, 8, 7.
3. Here we find that the no of valence electrons of element is 7 as the valence shell has 7 electrons.
4. So know we easily understand that the group is 7 because the no of valence electrons is 7.
5. Now to find the period we have to understand that the period is the number of shell the element is having therefore here chlorine has 3 shells (K-2, L-8, and M-7). So the period of the given element is 3.
Thus the position of the given element (here chlorine) is …..
Group
VII A (17th)
B’COZ VALENCE ELECTRONS = 7
Period
3rd
B’COZ NO OF SHELLS = 3
NB: Valency 8 refers to the group 0 and the element must be a Noble Gas.
Like this we can find the position of any non-transitional element. Now to find the Properties we have to see that where the element is located at the periodic table. We have already found it. So now let us see in which group it is at. Here chlorine is taken as example so chlorine is located at VII A group. Now as it is in VII A group we can understand that it’s a non-metal. It can also be concluded that the element belongs to Halogen Family and is a halogen. From here also we could see valency=8-7=1(chlorine is a non-metal, it can accept only one electron). Thus all basic properties are found.
Therefore, we can find the position of an element in periodic table and also the properties like this. The only thing we have to memorize is the Atomic number.
Hope this is helpful to you.....
Follow me....
Keep smiling........