Do the following triads form Dobereiner triads?

Discussion in 'CBSE Class 10 Chemistry Help' started by phani, Jan 13, 2012.

  1. phani

    phani Member Staff Member

    i. Li, Na, K
    ii. N,P, As

    i. The atomic mass of
    Lithium (Li) = 6.9
    Sodium (Na) = 23.0
    Potassium (K) = 39.1
    The average mass of Li and K is 23.0 which is the mass of sodium,
    So this triad forms a Dobereiner triad.


    ii. The atomic mass of
    Nitrogen (N) = 14.0
    Phosphorus (P) = 31.0
    Arsenic (As) = 74.9
    The average mass of N and As is 44.45 which is not equal to the mass of P. So it does not form a Dobereiner triad.

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