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Write the electronic configuration of K and Ne.
Concept: Periods and Electronic Configuration
The atomic masses of three elements A, B and C having similar chemical properties are 7, 23 and 39, respectively.
- Calculate the average atomic mass of elements A and C.
- Compare the average atomic mass with atomic mass of B.
- What could the elements A, B and C be?
Concept: Periods and Electronic Configuration
Classify the following elements into metals, non-metals and metalliods
As, C, Hg, Mg, S, Si
Concept: Periods and Electronic Configuration
Write the merits of the modern periodic table over Mendeleev’s Periodic table
Concept: The Modern Periodic Table
Differentiate between Normal elements and Transition elements.
Concept: Periods and Electronic Configuration
Write the name and symbol of the element from the description.
The atom having the smallest size.
Concept: Periodic Properties >> Atomic Size
Write the name and symbol of the element from the description.
The atom having the smallest atomic mass.
Concept: Periodic Properties >> Atomic Size
Write the name and symbol of the element from the description.
The most electronegative atom.
Concept: Gradation in Halogen Family
Write the name and symbol of the element from the description.
The noble gas with the smallest atomic radius.
Concept: Periodic Properties >> Atomic Size
Write a scientific reason.
Metallic character goes on decreasing while going from left to right in a period.
Concept: Metallic and Non-metallic Characters
Write the names from the description.
The metalloids in the second and third periods.
Concept: The Modern Periodic Table >> Structure of the Modern Periodic Table
Write the names from the description.
Non-metals in the third period.
Concept: The Modern Periodic Table >> Structure of the Modern Periodic Table
Write the names from the description.
Two elements having valency 4.
Concept: The Modern Periodic Table >> Structure of the Modern Periodic Table
What would be the correct order if Zn, Fe, Al and Cu are arranged in increasing order of reactivity?
Concept: The Modern Periodic Table
Atomic number of metal ‚A‛ is 11, while atomic number of metal ‚B‛ is 20. Which of them will be more reactive? Write the chemical reaction of dilute HCl with metal ‚A‛.
Concept: Periods and Electronic Configuration
An element has its electron configuration as 2,8,2. Now answer the following questions.
i. What is the atomic number of this element?
ii. What is the valency of this element?
iii. What is the group of this element?
iv. To which period does this element belong?
v. With which of the following elements would this element resemble?
`_7N , _4Be , _18Ar , _17CL`
Concept: The Modern Periodic Table >> Modern Periodic Table and Electronic Configuration of Elements
The halogen which is liquid at room temperature is ..................
Concept: Gradation in Halogen Family
iii) Observe the figure and answer the following questions.
a) Identify the block shown by box A and write an electronic configuration of any one element of this block.
b) Identify the block of element denoted by letter B and write its period number.
Concept: Metallic and Non-metallic Characters
Which of this element belong to the period 3? Write their electronic configuration
`3^(Li) , 14^(Si) , 2^(He) , 15^(P)`
Concept: The Modern Periodic Table >> Modern Periodic Table and Electronic Configuration of Elements
Study the radius of the element given below and answer the following questions.
| elements | K | Na | Rb | Cs | Li |
| Atomic radius (pm) | 231 | 186 | 244 | 262 | 151 |
a) Which of the above elements have the smallest atom?
b) In which group of the modern periodic table the above element are belongs?
c) What is the periodic trend observed in the variation of atomic radii down a group?
Concept: Periodic Properties >> Atomic Size
