Dobereiner's Law of Triads

Q.

Fill in the blanks based on features of Mendeleevs periodic table:

The vertical columns are called -------- and there are --------- groups.

Q. Which of the following statements are true regarding Dobereiner's periodic table?

1. The elements are written in the increasing order of atomic masses.
2. Similar elements occur after an interval of seven elements.
3. The mass of middle element was roughly the average of atomic masses of other two elements.
4. Elements in a triad show similar properties.

Q. Elements A and B are following Newland's law of octaves. If the number of elements lying between A and B is ‘x’, then the value of 2x will be:​

1. 10
2. 8
3. 16
4. 12