The properties of elements are a periodic function of their atomic weights.
a) Who proposed this law?
b) Can you see anything wrong in this law? If yes, justify your answer.
c) State modem periodic law.

The physical and chemical properties of elements are periodic functions of their atomic numbers. a) The atomic number of an element 'X' is 19. Write the group number, period and block to which 'X' belong in the periodic table. b) Name the element with i) highest electronegativity and ii) highest electron gain enthalpy

State the modern periodic law of elements.

Mosely modified Mendeleev's periodic law based on his observation on the X-ray spectra of elements. State the modern periodic law.

Statement 1: 'Atomic mass is the fundamental property of an element.' Statement 2: 'Atomic number is a more fundamental property of an element than its atomic mass.' a) Which statement is correct? Justify your answer. b) Name the scientist who proposed this statement? What observation led him to this conclusion?

Who introduced the periodic law of elements for the first time? State the law.

Development of priodic table have made the study of elements and their compounds easiere State the madern periodic law

Which of the following is not a merit of Mendeleev's original periodic table? a) Prediction of undiscovered elements and their properties b) Correction of atomic masses of a few elements c) Systematic arrangement of elements based on atomic mass d) Similar elements were placed in different groups e) Separate positions are given for isotopes f) Order of increasing atomic weight is not observed. The correct code is

A given compound always contains exactly the same proportion of elements by weight'. Write the name of the scientist who proposed this law..

According to Newton's law of motion,the force depends on the rate of change of momentum. State whether the force is external or internal?Justify your answer.

Mosely modified Mendeleev's periodic law based on his observation on the X-ray spectra of elements. Analyse the following graph, between ionization enthalpy and atomic number. What do you observe from the graph? Give justification for your observation.