Very Short Answer Questions - 1 Mark

Que 1. What was Döbereiner's basis of classifying elements?

Ans. According to Döbereiner, elements having similar properties can be arranged
in triads in which atomic mass of the middle element is the mean of the atomic masses of the other two elements

Que 2. State Mendeléev's Periodic Law.

Ans. Mendeléev's Periodic Law states that, "The properties of the elements are periodic function of their atomic masses

Que 3. State Newlands' Law of Octaves.

Ans. Newlands' Law of Octaves states that "when elements are arranged in order of increasing atomic weights, then every eighth element has properties similar to that of the first element."

Que 4. What was the drawback of the Law of Octaves?

Ans. Law of Octaves failed to assign the position to the elements with large atomic weights.

Que 5. Who classified the elements on the basis of fundamental properties of elements like atomic mass?

Ans. Mendeléev

Que 6. Define groups.

Ans. The vertical columns in the long form of the Periodic Table are called groups.

Que 7. What do you understand by periods in the Periodic Table? 

Ans. The horizontal rows in the long form of the Periodic Table are called periods. 

Que 8. In how many groups and periods, the Modern Periodic Table of elements is divided?

Ans. 18 groups and 7 periods.

Que 9. Name the elements present in the first period.

Ans. Hydrogen and helium

Que 10. Which period is the longest period in the Modern Periodic Table?

Ans. The sixth period is called the longest period because it has maximum 32 elements.

Que 11. How many vertical columns are there in the Modern Periodic Table?

Ans. In the Modern Periodic Table, there are 18 vertical columns of elements called group.

Que 12. Out of Li, C and N, which forms the most basic oxide and which forms the most acidic oxide?

Ans. Lithium forms the most basic oxide as it is a metal and nitrogen forms the most acidic oxide as it is a non-metal.

Que 13. A metal M belongs to 13th group in the Modern Periodic Table. Write the valency of the metal.

Ans. Atomic number = 13 (Al)      

         Electronic configuration = 2, 8, 3 ]

         Valency = 3 

Que 14. Find the period and group of the element whose atomic number is 12.

Ans. 3rd period, 2nd group.