शुरुआती दिनों में, तत्वों के वर्गीकरण का प्रयास मुख्य रूप से उनके किस आधार पर किया गया था?

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