Question

1. what pattern did newlands observe in the law of octaves? a. every 3rd element has similar properties b. every 4th element is reactive c. every 8th element has similar properties d. elements increase in alphabetical order 3. which scientist arranged elements by increasing atomic mass and predicted undiscovered elements? a. dalton b. mendeleev c. bohr d. thomson 4. how many elements were in a triad? a. 2 b. 3 c. 5 d. 8 5. which of the following had the most accurate predictions of missing elements? a. newlands b. lavoisier c. döbereiner d. mendeleev

Explanation:

1. In Newlands' Law of Octaves, he observed that every 8th element has similar properties when arranged in order of increasing atomic mass.
2. Mendeleev arranged elements by increasing atomic mass and predicted undiscovered elements. His periodic table had gaps for elements yet - to - be - discovered.
3. In Dobereiner's triads, there were 3 elements in each triad where the properties of the middle element were related to the other two.
4. Mendeleev had the most accurate predictions of missing elements among the given scientists. His periodic table was a significant step in the organization of elements.

Answer:

1. C. Every 8th element has similar properties
2. B. Mendeleev
3. B. 3
4. D. Mendeleev