Write down the contribution of John Dalton and Prout in the classification of elements.

The contribution of fohn Dalton in the classification of elements is that he profounded the atomic theory and said that the atoms of different elements have different atomic weights.

The contribution of Prout is that he said the atomic weight of an element is a simple multiple of the atomic weight of hydrogen.

The table below gives information about the atomic structure of some elements. Elements Protons Electron Arrangement Group in periodic table Metal and Non- metal  A 6 .................. 14 Non...

a.

c. Ans: Elements that exist in monoatomic molecules are elements A (carbon), element B (potassium) and element C (Neon). All the elements from above table exists in a monoatomic molecule...

1.    Name the type of bonds which are present in ice. 2.    Explain O-hydroxy Benz aldehyde and P-hydroxy Benz aldehyde, which is more soluble in water and why?3.    Lone pairs of electrons p...

1. Name the type of bonds which are present in ice.

Ans: The type of bond present in ice are: 1. Covalent bond    2. Hydrogen bond

2. Explain O-hydroxy Benz aldehyde and P-hydroxy Benz aldehyde, which is more soluble in water and why?

Ans: P-hydroxy benzaldehyde is more soluble in water than o-Hydroxy benzaldehyde, because P-Hydroxy benzaldehyde can form hydrogen bonds with water molecules resulting in enhanced solubility.

3.   Lone...

Lanthanides and actinides are kept below the main table. Why?

We know, lanthanides are rare earth metals, and actinides are radioactive metals. The properties of lanthanides resemble each other very closely but are different from the rest elements due to the preferential filling of f-orbitals. So, they are placed separately to avoid unnecessary sidewise expansion of the periodic table.

Elements of the zero group are called inert gases. Why?

We know, every element of the zero group has achieved stable electronic configuration being duplet stable or octet stable They have the valency zero and do not take part in any chemical reaction. So, elements of the zero group are called inert gas.

What are s-block and p-block elements? Write down their position modern periodic table.

The elements where the last electron enters in s-orbital are called s-block elements.
The elements where the last electron enters the p-orbital of the outermost shell are called p-block elements.

The position of s-block elements is IA and IIA groups.
The position of p-block elements are from IIIB to IIB group in the periodic table

Describe Newlands law of octaves saith a suitable example.

Newlands law of octaves stated, 'Elements when arranged increasing order of their atomic weights show resemblance in physical and chemical properties between the eight and first element is similar to the eight and first notes on a musical scale.

For example, potassium is the eight element after sodium.
These elements have similar physical and chemical properties.

Reactivity of metals increases while moving from top to bottom of the group. Why?

When we move from top to doon of periodic groups of metals, the atomic size increases gradually. Due to this, nuclear attraction to the valence electron decreases. As a result, the tendency of metal atoms to lose electrons increases. Hence chemical reactivity of metals increases when moving from top to bottom in a group.