Question

PLEASE ANSWER ALL 4 THANK YOU VERY MUCH!!!!

1. How was the Periodic Table originally organized? Explain the current organization of the Periodic Table and why it is a more accurate layout of the elements.

2. What is the difference between groups and periods? What are the common names for groups IA, IIA, VIIA, VIIIA?

3. Why were elements in group 18, VIIIA, formerly known as inert gases? How is the current name of “noble gases” more appropriate? Provide examples of involved elements.

4. Hydrogen can belong to two groups on the Periodic Table, what are they? Which group do you believe hydrogen fits best in? Explain why.

Answer 1

The first attempt was made by Antoine Lavoisier in late 1800 centuries but since then it almost took 100 years to make a rationalised periodic table. It was first done by Dmitri Mendeleev and contribution also made by Meyer. Mendeleev formed his periodic table on increasing trend of atomic weights of the elements. Thus Hydrogen came first at top of the table then comes Helium at top end of the table then comes Lithium, Boron and so on.

So first periodic table was made on the basis of the atomic weight of elements.

But after This was erroneous. Many trend predicted with this didn't match the practical measures. A more rational periodic table is formed via arranging the elements with the increase of their atomic number. This periodic table is called 'Modern Periodic Table". This is used most widely.

2. A table is constructed with several rows and columns. In Periodic Table the elements having same valence shell configuration are put into same column and called as groups. Whereas row wise arrangement of elements with their increasing number of atomic number is called period. Doing so we obtained 7 periods and 18 groups in Modern Day periodic table. Mendeleev's periodic table was constructed with 8 groups and 7 periods.

Generally having same valence shell configuration implies that the elements do possess same kind of properties. Thus elements belongs to same group seem to have same properties. Some of the groups are popular with a common name because of that reason.

IA - alkali metals

IIA- alkali earth metals

VIIA- Halogen

VIIIA - inert gas or noble gas

3. Tendency of an element to go in a reaction is dependent on its electronic configuration. It is told in octate law that every element will have maximum 8 electrons in its valence shell. As it is the maximum numbers of electrons a shell can have, so elements having those numbers electrons in its valence shell will not any affinity towards electrons and they have most stable state. Though in case of Helium the number of electrons in its valence shell is 2 as it valence shell can have maximum 2 electrons in it final shell. So it can be concluded that elements have filled up valence shell will not have any electron affinity and thus have no tendency to take part in reaction. They are inert in nature. The elements belong to VIIIA are of such kind and they are gaseous in nature. That's why these elements are also known as inert gas.

This non reacting property in human society is known as 'noble quality'. That's why inert gases is also known as noble gas.

Example - Helium, Argon, Neon, Krypton, Xenon

4. Hydrogen is element which has only one electron in his final shell and also has space for one electron. That's it can be associated in two groups in Periodic Table which are group IA or alkali metals group and group VIIA i.e. halogen group.

But in my opinion hydrogen is best fit in alkali metal group. This can be supported with electronegativity of the element. Electronegy is the property is depicting electron affinity of the element in compound. All the elements in halogen family are highly electro negative unlke hydrogen. Whereas alkali metals are electro positive in nature like hydrogen. That's why hydrogen belong to group IA.