Question 11 : why was newlands law of octaves
many radioactive elements had not been discovered then
elements were arranged in increasing order of atomic mass
the cycle of repetition shown by elements is similar to octave in music
it could not hold good for elements heavier than calcium

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.

From the options provided for each element below, choose the properties that it may have based on its location in the periodic table fluorine (f): highly reactive nonmetal shiny a conductor

1) which of the following is the best example of a physical change? a) sugar dissolving in tea b) firefly glowing 2) in the combustion of ethane, what is/are the reactants? c2h6 + o2 ==> co2 + h2o a) c2h6 and o2 b) co2 and c2h6