a) What is the valency of carbon?

b) How many electrons are needed for carbon to attain octet configuration?

c) Draw the electron dot diagram of methane (CH₄), the compound formed by the combination of Carbon and Hydrogen

N☰N   represents a molecule.

Choose the type of chemical bonding present here.

( Ionic bond,single bond,double bond,triple bond )

The atomic number of fluorine is 9

Draw the electron dot diagram of the formation of fluorine molecule by the combination of two fluorine atoms ‍

The given elements do not take part in chemical reactions usually.

Why do these elements have stability?Explain on the basis of their electronic configuration .

Given below are the electronic configurations of a few elements.(symbols are not real)

A - 2,8,8,2    B – 2,8,8

C– 2,8,1       D – 2,8,7

a) Which one of these atoms accepts electrons?

b) Which is the stable element?

c) Write down the molecular formula of the compound formed when the elements A and D combine together?

d) Which element has a valency of two ?

Electronegativity values of a few elements are given.

   H – 2.20        Ca – 1.00     O – 3.44

   C – 2.55           Cl – 3.16   Mg – 1.31

a) Which type of chemical bond is present in the given compounds?

(i) MgO     (ii) CaCl₂      (iii) HCl

b) Which one of these form a polar compound?

Electronic configurations of a few elements are given.Analyse them and answer the following questions.

 K - 2,8,8,1              Ar – 2,8,8

Cl – 2,8,7               Mg – 2,8,2

a) Which of these elements form cations?

b) Which element doesnot take part in chemical reactions? Give reason.

c) Write down the molecular formulae of two compounds that are possible here.

The elements calcium and oxygen combine to form calcium oxide molecule .(atomic number :calcium -20, oxygen- 8)

a) Draw the electron dot diagram of the formation of calcium oxide molecule.

b) Write down the molecular formula of calcium oxide.

c) What is the valency of calcium?

Molecular formula of aluminium chloride is AlCl_3.( atomic number Al-13,Cl- 17)

a) Which type of chemical bonding is present in AlCl₃?

b) What is the charge on aluminium ion in AlCl₃ ?

c) What is the valency of chlorine ?

d)How many electrons are present in the outermost shell of aluminium ion?

Analyse the table and write down the molecular formulae of the compounds given below

a)Magnesium Chloride

b) Aluminium Oxide

The figure given below represents the Electron dot diagram of the formation of HCl molecule .

IMAGE

a) The formation of chemical bond in HCl molecule is by -------------

(electron transfer/ electron sharing ‍ )                                  (1)

b) What is the type of chemical bond  formed here known as? (1)

c) H-Cl shows polar nature. Why? (2)

The Electron dot diagram representing the formation of oxygen molecule is given below.

IMAGE

a) How many pairs of electrons are shared between the oxygen atoms ?

Mention the type of covalent bond present here? (

b) Electronic configuration of Nitrogen is 2,5 .Draw the electron dot diagram of the formation of N₂ molecule.

The figure given below represents the Electron dot diagram of the formation of sodium oxide .

image

a) What are the valencies of sodium and oxygen.?

b) Which one of these elements donates electrons ?Which element accepts electrons? 

c) Identify the type of chemical bond present  in the given molecule 

The figure given below represents the electron dot diagram of Sodium Chloride formation.

image

a) Identify the type of chemical bonding present in sodium chloride

b) Given the electronic configurations of the elements Mg and F

Mg - 2,8,2 ; F - 2,7

When magnesium and fluorine combine,

i)which element donates its electrons to the other? ‍

ii)How many electrons are donated ?

c) Draw the electron dot diagram of the formation of magnesium fluoride . ‍

1 .              Ar-  2,8,8

The given element Argon does not take part in chemical reactions.

a)Which among the following elements undergo chemical reactions forming compounds?. Give reason

(i) Ca – 2,8,8,2          ii) Ne - 2,8

iii) Kr - 2,8,18,8           iv ) S - 2,8,6

b) The attractive force that holds together the atoms in a molecule is known as ---------------------------------