Some households in a locality are sorted according to their electricity usage in the table below.
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(a) If the household using the least unit of electricity is numbered as one and second least as two and so on, what is assumed to 'be usage of electricity of the '21^ st ' household.
(b) Calculate the median usage of electricity.

Some information related to the elements of the p block in the 17th group of the periodic table are given in the table below. Complete the able and analyse the following questions. a) What is the family name of element belonging to 17th group? b) what is their common valency? c) Which element has the highest electronegativity? d) Which element has highest ionisation energy? e) List out the name and chemical formula of the compounds formed by this elements with s block elements. '(##VPU_TTT_CHE_X_P01_C01_E02_002_Q01##)'