आवर्त सारणी के आवर्त 2 और समूह 17 में रखे गए एक तत्व X की परमाणु संख्या क्या होगी?

Which classification law of chemical elements was proposed by J.A.R. Newlands in 1865?

Match the group numbers with their corresponding element family names: i. III A (Group 13) ii. IV A (Group 14) iii. VI A (Group 16) iv. VII A (Group 17) a. Chalcogen family b. Halogen family c. Boron family d. Carbon family