Demerits of Newland's Law of Octaves

Q. The atomic masses of Nickel (Ni) and Cobalt (Co) are 58.7 and 58.9 respectively. Identify the element that was placed first according to the Mendeleev’s periodic table.

1. Ni was placed before Co.
2. Co was placed before Ni.
3. Both were placed in the same group.
4. Ni and Co were not discovered.

Q. In Mendeleev's periodic table, the elements were arranged in the increasing order of their atomic masses. However, cobalt with atomic mass of 58.93 amu was placed before nickel having an atomic mass of 58.69 amu. Reason for the same is that :

1. the elements with similar size can be grouped together
2. the elements with different properties can be grouped together
3. the elements with similar properties can not be grouped together
4. the elements with similar properties can be grouped together

Q. The elements in the Mendeleev’s periodic table were arranged in the increasing order of their atomic masses. But, the sequence was inverted so that two elements with similar properties could be grouped together. Identify those two elements.

1. Cobalt (Co) and Nickel (Ni)
2. Potassium (K) and Calcium (Ca)
3. Lithium (Li) and Sodium (Na)
4. Beryllium (Be) and Magnesium (Mg)

Q.

How many groups and periods are there in the Mendeleev's periodic table?

1. There are six groups and seven periods.

2. There are eight groups and seven periods.

3. There are seven groups and seven periods.

4. There are eight groups and six periods.

Q. For which of the following elements the sequence of increasing atomic masses was inverted in Mendeleev’s periodic table?

1. Lithium (Li) and sodium (Na)
2. Cobalt (Co) and nickel (Ni)
3. Potassium (K) and calcium (Ca)
4. Beryllium (Be) and magnesium (Mg)

Q. Write two achievements of Mendeleev’s periodic table.

Q. Which of the following statements is correct?

1. Law of octaves worked quite well for heavier elements but failed for lighter elements.
2. Law of octaves failed for both lighter elements and heavier elements.
3. Law of octaves worked quite well for lighter elements but failed for heavier elements.
4. Law of octaves was first given by Mendeleev.

Q. Hydrogen exhibits the properties similar to both alkali metals and halogens.

1. True
2. False

Q.

Identify the correct statement about Nickel and Cobalt according to the Mendeleev’s periodic table.

1. Ni and Co were not discovered

2. Co was placed before Ni

3. Both were placed in the same group

4. Ni was placed before Co