Selina solutions concise chemistry class 9 icse Solutions for Chapter 4 chapter 4 atomic structure and chemical bonding

What are the cathode rays? How are these rays formed?

What is the nature of charge on

(i) cathode rays

(ii) anode ray

How are X-rays produced?

Why -were.anode rays also called as ‘canal rays’?

How do cathode rays differ from anode rays?

a) Name an element that does not contain neutron.

b) If an atom contains one electron and one proton, will it carry any charge or not?

Which sub-atomic particle was discovered by

(a) Thomson

(b) Goldstein

(c) Chadwick.

On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?

How was it shown that an atom has empty space?

State one major drawback of Rutherford’s model.

What should be the ratio of area of cross section of the master cylinder and wheel cylinder of a hydraulic brake so that a force of 15N can be obtained at each of its brake show by exerting a force of 0.5N on the pedal?

Complete the table given below by identifying P, Q, and R

The atomic number and mass number of sodium are 11 and 23 respectively. What information is conveyed by this statement

Write down the names of the particles represented by the following symbols and explain the meaning of superscript and subscript numbers attached

From the symbol state the mass number, the atomic number, and the electronic configuration of magnesium.{ }_{12}^{24} M g

Sulphur has an atomic number 15 And the mass number of 32.

State the number of protons and neutron in the nucleus of sulphur. Give a simple diagram to show the arrangement of electrons in an atom of sulphur

Explain the rule according to which electrons are filled in various energy levels

Draw the orbital diagram Ca+2 ion and state the number of three fundamental particles present in it

Write down the electronic configuration of the following

Write down the number of electrons in X and neutrons in Y.

a) What are the inert elements?

b) Why do they exist as monoatomic in molecules?

c) What are valence electron

In what respect do the three isotopes of hydrogen differ ? Give their structures

Draw diagrams representing the atomic structures of the following

(a) Sodium atom (b) Chloride ion

(c) Carbon atom (d) Oxide ion.

Elements X, Y, and Z have atomic numbers 6, 9, and 12 respectively. Which one :

(a) forms an anion (b) forms a cation

(c) has four electrons in its valence shell?

Element X has electronic configuration 2, 8, 18, 8, 1. Without identifying X,

a) Predict the sign and charge on a simple ion of X.

b) Write if X will be an oxidizing agent or reducing agent. Why?

From the symbol ?? ? ?

for the element helium, write down the mass number and the atomic number of

the element

\frac{24}{12} M g \text { and } \frac{26}{12} M g \text { are symbols of two isotopes of magnesium }

(a) Compare the atoms of these isotopes with respect to :

(i) the composition of their nuclei.

(ii)their electronic configurations.

(b) Give reasons why the two isotopes of magnesium have different mass numbers

What are nucleons? How many nucleons are present in phosphorus? Draw its structure.

Explain fractional atomic mass. What is the fractional mass of chlorine?

Name the following :

(a) The element which does not contain any neutron in its nucleus.

(b) An element having valency `zero’.

(c) Metal with valency

(d) Two atoms having the same number of protons and electrons but a different number of neutrons.

(e) The shell closest to the nucleus of an atom.

Give reasons

(a) Physical properties of isotopes are different

(b) Argon does not react.

(c) The actual atomic mass is greater than the mass number.

(d) \text { (d) }{ }_{17}^{35} C l \text { and }{ }_{17}^{3}{ }^{C} C l \text { do not differ in their chemical reactions. }

Choose the correct option

(a) Rutherford’s alpha-particle scattering experiment discovered

A. Electron

B. Proton

C. Atomic nucleus

D. Neutron

(b) The number of valence electrons in 0-2 is :

A. 6

B. 8

C. 10

D. 4

(c) Which of the following is the correct electronic configuration of potassium?

A. 2, 8, 9

B. 8, 2, 9

C. 2, 8, 8, 1

D. 1, 2, 8, 8

(d) The mass number of an atom whose unipositive ion has 10 electrons and 12 neutrons is :

A. 23

B. 22

C. 20

D. 21 23.

Explain (a) octet rule for the formation of a chemical compound. (b) duplet rule for the formation of hydrogen.

Complete the following table relating to the atomic structure of some elements.

How do atoms attain a noble gas configuration

Define electrovalent bond.

What type of compounds are usually formed between metals and non-metals and why?

(a) In the formation of the compound XY2 , an atom X gives one electron to each Y atom. What is the

nature of bond in XY 2?

(b) Draw the orbit structure of this compound (XY2).

a) Nature of bond in XY2 is an ionic bond.

b) Orbit structure of XY2

Compare :

(a) sodium atom and sodium ion

(b) chlorine atom and chloride ion, with respect to

(i) atomic structure, (ii) electrical state

The electronic configuration of fluoride ion is the same as that of a neon atom. What is the difference

between the two?

Covalent bonds can be a single, double, or triple covalent bonds. How many electrons are shared in each?

Give an example of each type.

Show the number of bonds in

(i) ethene molecule

(ii) ethyne molecule

Match the atomic numbers 4, 8, 10, 15, and 19 with each of the following

(a) Element which can form a trivalent ion.

(b) An element with 4 shells.

(c) Element with 6 valence electrons.

(d) An element which does not form an ion.

If electrons are getting added to an element Y; then

(a) is Y getting oxidized or reduced?

(b) what charge will Y migrate to during the process of electrolysis

(a) Elements X, Y, and Z have atomic numbers 6, 9, and 12 respectively. Which one

i) forms an anion, (ii) forms a cation,

b) State the type of bond between Y and Z and give its molecular formula

An element M burns in oxygen to form an ionic compound MO. Write the formula of the compounds formed if this element is made to combine with chlorine and sulphur separately.

Give the orbital diagram of the following :

(a) magnesium chloride, (b) nitrogen,

(c) methane (d) hydrogen chloride

State the type of bonding in the following molecules.

(a) water, (b) calcium oxide, (c) hydrogen chloride

Metal M forms a chloride with the formula MC12. What type of bond in MC12. Write the formula of

the compound when M combines with sulphur, oxygen, and nitrogen.

Choose the correct answer from the choices A, B, C and D:

(i) The characteristic of a covalent compound is that:

A. they are farmed by the sharing of electrons.

B. they are formed between metals and non-metals.

C. they are formed between two non-metals.

D. they often exist as a liquid.

(ii) When a metal atom becomes an ion

A. it loses electrons and is oxidized,

B. it gains electrons and is reduced,

C. it gains electrons and is oxidized,

D. it loses electrons and is reduced

Identify the following reactions as either oxidation or reduction:

i) O + 2e- O-2

ii) K-e- K+

iii) Fe+3 + e- Fe+2

iv) Zn Zn+2 + 2e-

a) Name the charged particles which attract one another to form electrovalent compounds.

(b) In the formation of electrovalent compounds; electrons are transferred from one element to another.

How are electrons involved in the formation of a covalent compound?

(c) The electronic confi.wration of nitrogen is (2, 5) How many electrons in the outer shell of a nitrogen

atom are not involved in the formation of a nitrogen molecule?

(d) In the formation of magnesium chloride (by the direct combination between magnesium and chlorine).

Name the substance that is oxidized and the substance that is reduced.

What is the term defined below?

(a) A bond formed by a shared pair of electrons, each bonding atom contributing one electron to the pair.

(b) A bond formed by transfer of electron(s).

An element X has 2 electrons in its M shell, it forms a bond with an element Y which has 7 electrons in its

third orbit.

a) Write the formula of the compound formed.

b) Which nearest inert gas electronic configuration will element X and Y acquire

c) Show by orbital diagram the formation of the compound between X and Y.

In the formation of

i) Oxygen molecule

ii) Carbon tetrachloride molecule, state the following.

a) Electronic configuration of nearest inert gas attained.

b) How many electrons are shared/transferred in bond formation?

c) Which type of bonds do compounds form?

d) Draw the orbital diagrams