Define the Term : Valency - Science

Advertisements
Advertisements

Define the term : Valency

Advertisements

Solution

Valency:-

The combining power or the combining capacity of an atom is called its valency. Valency of an atom is simply equal to the number of electrons gained, lost or shared by an atom to achieve the nearest noble gas configuration.

  Is there an error in this question or solution?
2013-2014 (March) Delhi Set 1

Video TutorialsVIEW ALL [2]

RELATED QUESTIONS

Fill in the blank:

The formulae of chloride of metal M is MCl2. The metal M belongs to ……………. group.


Elements in the same group show the same valency. Give scientific reason.


Write the electronic configuration of K and Ne.


The atomic masses of three elements A, B and C having similar chemical properties are 7, 23 and 39, respectively.

  1. Calculate the average atomic mass of elements A and C.
  2. Compare the average atomic mass with atomic mass of B.
  3. What could the elements A, B and C be?

Calcium is an element with atomic number 20. Stating reason, answer each of the following questions:-

(i) Is calcium a metal or a non-metal?

(ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19?

(iii) Write the formula of its oxide.


How do the atomic size and metallic character of elements vary as we move :-

(a) down a group and

(b) from left to right in a period


Write the number of vertical columns in the modern periodic table. What are these columns called?


Classify the following elements into metals, non-metals and metalliods

As, C, Hg, Mg, S, Si


Calculate the mass of Calcium that will contain the same number of the atom as are present in 3.2 gm of Sulphur.

[Atomic masses: S=32, Ca=40]

 


Differentiate between Normal elements and Transition elements.


Fill in the blank in the following statement:

The tendency to gain an electron ............... on moving down in a group of the periodic table.


What happens to the metallic character of the elements as we move from left to right in a period of the periodic table?


The electronic configuration of the atom of an element X is 2, 8, 4. In modern periodic table, the element is places in :

(a) 2nd group
(b) 4th group
(c) 14th group
(d) 8th group


Name two properties of elements whose magnitudes change when going from top to bottom in a group of the periodic table. In what manner do they change?


Which one of the following does not increase while moving down the group of the periodic table?


In each of the following pair, choose the atom having the bigger size:

Na (At. No. 11) or K (At. No. 19)


Name the type of elements .

two outermost shell incomplete – ………………


Name the type of elements .

two electrons in the outermost orbit - ……………


An element A has atomic number 14. To which period does this element belong and how many elements are there in this period.


An element 'M' has atomic number 12.

(a) Write its electronic configuration.

(b) State the group to which 'M' belongs.

(c) Is 'M' a metal or a non-metal.

(d) Write the formula of its chloride.


What will be the valency of an element of atomic number 9 (nine)?


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‛.


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
  1. Arrange the above elements in decreasing order of their atomic radii.
  2. State the period to which the above elements belong.
  3. Why this arrangement of elements is similar to the above period of modern periodic table?
  4. Which of the above elements have the biggest and the smallest atom?
  5. What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?

How many groups and periods are there in the modern periodic table?


Select the correct answer
Identify the metalloid


Parts (i) to (v) refer to changes in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the letter corresponding to the correct answer from the choices (a), (b), (c) and (d).
(i) The non metallic character of the elements:
(a) Decreases
(b) Increases
(c) Remains the same
(d) Depends on the period
(ii) The electro negativity
(a) Depends on the number of valence electrons
(b) Remains the same
(c) Decreases
(d) Increases
(iii) The ionization potential
(a) Goes up and down
(b) Decreases
(c) Increases
(d) Remains the same
(iv) The atomic size
(a) Decreases
(b) Increases
(c) Remains the same
(d) Sometimes increases and sometimes decreases
(v) The electron affinity of the elements in groups 1 to 7:
(a) Goes up and down
(b) Decreases and then increases
(c) Increases
(d) decreases


Arrange the following as per instruction given in the bracket.

Mg, Cl, Na, S, Si (decreasing order of atomic size) 


Parts (a) to (e) refer to change in the properties of elements on moving from left to right across a period of the periodic table. For each property, choose the correct answer. 

The non-metallic character of the elements:


The elements of one short period of the periodic table are given below in order from left to right: 

Li Be B C O F Ne 

Place the three elements: Fluorine, Beryllium and nitrogen in the order of increasing electronegativity


The position of elements A, B, C, D and E in the periodic table are shown below:

Group 1

Group 2

Group 17

Group 18

 

 

 

D

 

B

C

 

A

 

 

E

Which type of ion will be formed by elements A, B, and C.

 


An element belongs to the third period and Group IIIA (13) of the periodic table. State: the name of the element. 


Name and state the following with reference to the elements of the first three periods of the periodic table.

Non-metallic elements present in Period 3 of Groups 15 and 16.


Write down the word that will correctly complete the following sentence:

Going across a period left to right, atomic size _____.


(a) Fill in the blanks and rewrite the completed statements: 

(i) ________ group in the periodic table contains elements that are all gases at room temperature. 

(ii) Very fine particles mainly scatter ______ light.


Fill in the blank and rewrite the completed statement:

________ group in the periodic table contains elements that are all gases at room temperature.


Give Scientific Reason:
Atomic size increase down the group.

Name the period which is the shortest period of the periodic table.


State the property trends in general of elements on moving from left to right in a period of the periodic table.


Name or state following with reference to the element of the first three periods of the periodic table.

The formula of the hydroxide of the element having electronic configuration 2, 8, 2.


Name or state following with reference to the element of the first three periods of the periodic table.

The valency of the element in period 3 having atomic number 17.


Name or state following with reference to the element of the first three periods of the periodic table.

A non-metal in period 2 which is tetravalent.


Give a reason for the following:

A transition from metallic to non-metallic elements is seen on moving from left to right in a period of the periodic table.


Share
Notifications



      Forgot password?
Use app×