NDA CHEMISTRY QUIZ - 18

Henry Moseley gave the graph between and atomic number which was found to be 

What were the limitations of Mendeleev periodic table ?

1. Position of isotopes explained by him 
2. No fixed position is given to hydrogen
3. Mendeleev place an element with a slightly greater atomic mass before an element with slightly low atomic mass 
4. In chemical properties , he consider reactivity with hydrogen and oxygen only .

An element A belongs to d block element , poisons the body’s system by interfering with sulphur containing enzymes and is found in liquid state at room temperature . Element A is 

Mendeleev concentrated on the compound formed by hydrogen and oxygen as-

1. They are very reactive 
2. They form a compound with most of the element 
3. They are least reactive 
4. Their concentration in the environment is very low

Which of the following elements called representative elements ?

Directions – Question consist of two statements labelled as statement I and statement II . Examine both the statement and mark the correct choice according to the codes given below 

Statement I – Noble gases exhibit low reactivity and high ionization enthalpy

Statement II –  Noble gases are completely filled by electrons 

Modern periodic table is based on atomic number . The experiment which proved the significance of atomic number is 

Transuranium elements are unstable and decay radioactively into other elements. These are-

Directions – Question consist of two statements labelled as statement I and statement II . Examine both the statement and mark the correct choice according to the codes given below 

Statement I – Noble gases were discovered very late . 

Statement II –  Noble gases are inert and have low concentration in the atmosphere  .

There are 3 elements A, B, and C.

1. An element – belongs to alkaline earth metals 
2. B element – belong to chalcogens family 
3. C element – belong to actinoids 

Which of the following option is correct based on the above information?