Science : Ch 05 – Periodic of Classification of Elements

Which of the following declaration about the modern periodic table is accurate?

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:

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?

Which of the subsequent is the outermost shell for elements of period 2?

Arrange these elements in increasing order of their atomic radii

Which of the following is the outermost shell for elements of period 2

Modern Periodic Law States that

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

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

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

The number of groups in the Modern Periodic Table

The atomic number of an element is 20, its electronic configuration.

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

Is calcium?