Advertisements
Advertisements
Elements in the same group show the same valency. Give scientific reason.
Concept: Periods and Electronic Configuration
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 scientific reason.
Atomic radius goes on increasing down a group.
Concept: Periodic Properties >> Atomic Size
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
Taking into consideration the period of the elements given below, answer the following questions:
| Elements | Atomic Radius (pm) |
| O | 66 |
| B | 88 |
| C | 77 |
| N | 74 |
| Be | 111 |
| Li | 152 |
- Arrange the above elements in decreasing order of their atomic radii.
- State the period to which the above elements belong.
- Why this arrangement of elements is similar to the above period of modern periodic table?
- Which of the above elements have the biggest and the smallest atom?
- What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?
Concept: Periods and Electronic Configuration
