Science : Ch 05 – Periodic of Classification of Elements

Which of the following affirmation about the modern periodic table are inappropriate?

1. The elements in the modern periodic table are arranged on the basis of their decreasing atomic numbers
2. The elements in the modern periodic table are arranged on the basis of their increasing atomic masses.
3. Isotopes are placed in adjoining group(s) in the periodic table.
4. The elements in the modern periodic table are arranged on the basis of their increasing atomic number

An element X with atomic number 12 forms a compound with element Y with atomic number 17. The formula of the compound formed is:

The elements A, B, C, D and E have atomic number 9, 11, 17, 12 and 13 respectively. Which pair of elements belongs to the identical group?

In Mendeleev’s periodic table, gaps were left for the elements to be discovered later. Which of the subsequent element found a place in the periodic table later?

As claimed by Mendeleev’s periodic law, the elements were arranged in the periodic table in the order of:

Which of the following elements does not lose an electron with ease?

Which of the following are the characteristics of isotopes of an element?

1. Isotopes of an element have the same atomic masses.
2. Isotopes of an element have the same atomic number
3. Isotopes of an element show the same physical properties.
4. Isotopes of an element show the same chemical properties.

Three elements B, Si and Ge are:

Arrange these elements in increasing order of their atomic radii

Which among the following has larger size of atoms?

How many metals are present in second period of periodic table?

The formulae of chlorides of Eka-silicon the elements predicted by Mendeleev.

The number of groups in the Modern Periodic Table

Arrange the following elements in increasing order of their atomic radii:

The atomic number of an element is 20, its valency is