Write the contribution of Mendeleef in the creation of the ‘periodic table’. [3]
OR
What is meant by the atomic radius of an atom? Arrange the first three elements C, Si and Ge of group 14 of long periodic table in the order of their increasing atomic radii. [2 + 1]
WBBSE
Class X
Physical Science
Periodic Table
03 Mark
2023
Mendeleev’s contributions to the creation of the periodic table include:
- Periodic Law: He arranged elements in order of increasing atomic mass and discovered that elements with similar properties appeared at regular intervals (periodicity).
- Predictions: Mendeleev left gaps in the table for undiscovered elements and accurately predicted their properties, such as gallium and germanium.
- Grouping of Elements: He successfully grouped elements with similar chemical properties into columns, establishing the foundation for the modern periodic table.
OR
The atomic radius of an atom is the distance from the center of the nucleus to the outermost shell of electrons. It represents the size of the atom.
For group 14 elements (C, Si, Ge):
C < Si < Ge
Related Questions
More WBBSE Moderate level questions
1/12
Q.
Explain the position of hydrogen in the modern periodic table. Which group of the periodic...
A.
Position of Hydrogen Hydrogen has the electronic configuration 1s¹. Like Group 1...
Q.
State Modern Periodic Law. Discuss the periodic trends of atomic radii for elements of Group...
A.
Modern Periodic Law The physical and chemical properties of elements are periodic...
Q.
What is the important conclusion of Moseley’s experiment? What is the importance of this conclusion...
A.
From Moseley's experiment, it was concluded that the atomic number, and not...
Q.
2.11.1. An alkaline earth metal (a) Fe 2.11.2. The metal which is present in the...
A.
2.11.1 → (c) Ca 2.11.2 → (a) Fe 2.11.3 → (d) K...
Q.
How many elements are there in the fourth period of long periodic table?
A.
b. 18 Explanation: The 4th period starts with Potassium (K, Z=19) and...
Q.
What is meant by ionisation energy of an atom of an element? Arrange Na, Rb,...
A.
Ionisation energy is the amount of energy required to remove an electron...
Q.
The first three elements of group 16 of long periodic table are O, S, and...
A.
Atomic Radius: Se > S > O Electronegativity: O < S <...
Q.
What is meant by the electronegativity of an element? How does the electronegativity of Group...
A.
Electronegativity is the tendency of an atom in a molecule to attract...
Q.
Match the right column with the left column: 2.11.1. Noble Gas (a) Cs2.11.2. Inver (b)...
A.
Left Column Right Column (1) Noble Gas (b) Rn (2) Inver (d)...
Q.
If the elements are arranged in ascending order of their electropositivity, then choose the correct...
A.
(b) C > N > 0 > F Explanation Electropositivity decreases from...
Q.
Mention similarity of properties of hydrogen with two properties of group 17 elements of long...
A.
Hydrogen shares similarities with group 17 elements (halogens) in the following ways:...
Q.
From which group to group 12 of the long periodic table are the transitional elements...
A.
The transitional elements are located from Group 3 to Group 12 of...