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# Selina solutions for Concise Chemistry Class 7 ICSE chapter 4 - Atoms, Molecules and Radicals [Latest edition]

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## Chapter 4: Atoms, Molecules and Radicals

ExerciseObjective type questionsAdditional questions
Exercise

### Selina solutions for Concise Chemistry Class 7 ICSE Chapter 4 Atoms, Molecules and Radicals Exercise

Exercise | Q 1.1

Define:- Atom

Exercise | Q 1.2

Define:- Molecule

Exercise | Q 1.3

Define:- Radicals

Exercise | Q 1.4

Define:- Valency

Exercise | Q 1.5

Define:- Periodic table

Exercise | Q 2.1

Write the names of the elements present in the:-

Common salt

Exercise | Q 2.2

Write the names of the elements present in the:-

Ammonia

Exercise | Q 2.3

Write the names of the elements present in the :-

Sulphuric acid

Exercise | Q 2.4

Write the names of the elements present in the:-

Glucose

Exercise | Q 2.5

Write the names of the elements present in the:-

Sodium hydroxide

Exercise | Q 2.6

Write the names of the elements present in the:-

Acetic acid

Exercise | Q 3.1

What does 2C02 represent ?

Exercise | Q 3.2

What does 2H2S  represent ?

Exercise | Q 3.3

What does 5H2S04 represent ?

Exercise | Q 3.4

What does 6NaNO3 represent ?

Exercise | Q 4

Write the symbols and valencies of the following radicals:

(a)Magnesium iron

(b) Amonium

(c)carbonate

(d)Nitrate

(e)Oxied

(f) Bisulphate

(g) Aluminium ion

Exercise | Q 5.1

Name the following radicals :

SO42

Exercise | Q 5.2

Name the following radicals :

HC03

Exercise | Q 5.3

Name the following radicals :

OH

Exercise | Q 5.4

Name the following radicals :

Cr2072

Exercise | Q 6.1

Name one ion for  each of the valencies +1, +2  and +3.

Exercise | Q 6.2

Name one ion for  each of the valencies-1, -2  and -3.

Exercise | Q 7

The valency of calcium is 2. Write the valencies of other radical in the following :

1. CaO
2. Ca(OH)2
3. CaC03
4. CaCl2
Exercise | Q 8.1

Write the names of ("NM"_4)_2"SO"_4 compounds :

Exercise | Q 8.2

Write the names of "Ca"("NO"_3)_2 compounds :

Exercise | Q 8.3

Write the names of "FeS" compounds :

Exercise | Q 8.4

Write the names of "Na"_3"PO"_4 compounds :

Exercise | Q 8.4

Write the names of "CuCo"_3 compounds :

Exercise | Q 8.5

Write the names of "NH"_4"OH" compounds :

Exercise | Q 8.6

Write the names of "HgO" compounds :

Exercise | Q 8.7

Write the names of "ZnCl"_2  compounds :

Exercise | Q 8.8

Write the names of ZnS compounds :

Exercise | Q 8.9

Write the names of "H"_2"S" compounds :

Exercise | Q 9.01

Write the molecular formulae of Sodiun sulphide:

Exercise | Q 9.02

Write the molecular formulae of Magenesium oxide :

Exercise | Q 9.03

Write the molecular formulae of Calcium hydroxide :

Exercise | Q 9.04

Write the molecular formulae of Hydrogen chloride :

Exercise | Q 9.05

Write the molecular formulae of Sulphuric acide :

Exercise | Q 9.06

Write the molecular formulae of Iron (II) sulphide :

Exercise | Q 9.07

Write the molecular formulae of Iron (III) sulphide:

Exercise | Q 9.08

Write the molecular formulae of Nitric acide :

Exercise | Q 9.09

Write the molecular formulae of Calcium phosphate :

Exercise | Q 9.1

Write the molecular formulae of Aluminium sulphate :

Exercise | Q 9.11

Write the molecular formulae of Magnesium nitride:

Exercise | Q 10.1

The valency of sodium is one, write the molecular formula for sodium oxide ?

Exercise | Q 10.2

The valency of sodium is one, write the molecular formula for sodium sulphate ?

Exercise | Q 10.3

The valency of sodium is one, write the molecular formula for sodium carbonate ?

Exercise | Q 10.4

The valency of sodium is one, write the molecular formula for sodium hydroxide ?

Exercise | Q 10.5

The valency of sodium is one, write the molecular formula for sodium nitratev ?

Exercise | Q 11

What is variable valency ? Give two examples of elements showing variable valency.

Exercise | Q 12

Give the group number of following elements present in periodic table

Exercise | Q 13

An element belongs to group VA. What would be its valency? Name two such elements.

Exercise | Q 14

An element belongs to group II. What would be its valency? Write the formula of molcules of compounds it will form with elements in VA, VIA and VIIA groups.

Objective type questions

### Selina solutions for Concise Chemistry Class 7 ICSE Chapter 4 Atoms, Molecules and Radicals Objective type questions

Objective type questions | Q 1.1

Fill in the blank:

Atoms are _____

Objective type questions | Q 1.2

Fill in the blank

An ion with positive charge is called ______

Objective type questions | Q 1.3

Fill in the blank

An ion with negative charge is called _______

Objective type questions | Q 1.4

Fill in the blank

2H2 means two _______ of hydrogen.

Objective type questions | Q 1.5

Fill in the blank

_______ is a triatomic molecule.

Objective type questions | Q 1.6

Fill in the blank

Metals have ______ valency.

Objective type questions | Q 1.7

Fill in the blank

Chemical name of caustic soda is _______

Objective type questions | Q 2.1

Tick (√) the correct answer.

The valency of iron in Fe203 is

• 1

• 2

• 3

• 6

Objective type questions | Q 2.2

Tick (√) the correct answer

Which of the following has valency 4 ?

• aluminium

• oxygen

• carbon

• phosphorus

Objective type questions | Q 2.3

Tick (√) the correct answer.

The sulphate radical is written as S042-. What is the formula of calcium sulphate ?

• Ca(S04)2

• Ca2(S04

• Ca(S04)

• CaS0

Objective type questions | Q 2.4

Tick (√) the correct answer.

Which of the following exhibit variable valency ?

• calcium

• copper

• carbon

• chlorine

Objective type questions | Q 3.1

State the term.

The number of atoms present in a molecule of an element _________

Objective type questions | Q 3.2

State the term

The symbolic representation of a molecule ______

Objective type questions | Q 3.3

State the term

A group of atoms that react as a single unit ______

Objective type questions | Q 3.4

State the term

The combining capacity of an element _______

Objective type questions | Q 3.5

State the term

The tabular arrangement of elements in horizontal rows and vertical columns _________

Additional questions

### Selina solutions for Concise Chemistry Class 7 ICSE Chapter 4 Atoms, Molecules and Radicals Additional questions

Additional questions | Q 1.1

Define: Ions

Additional questions | Q 1.2

Define: Chemical bond

Additional questions | Q 1.3

Define: Atomic number

Additional questions | Q 1.4

Define: Mass number

Additional questions | Q 1.5

Define: Relative atomic mass

Additional questions | Q 2

What does an atom consist of ? Explain.

Additional questions | Q 3

Give the charge and the mass of an electron, proton and neutron present in an atom ?

Additional questions | Q 4

Name two particles found inside the nucleus. What are they collectively called ?

Additional questions | Q 5.1

Name the particles which revolve around the nucleus.

Additional questions | Q 5.2

What are orbits or shells ?

Additional questions | Q 5.3

What is the maximum number of electrons present in:

1. first shell
2. second shell
3. third shell and
4. fourth shell

Additional questions | Q 6.1

Elements X and Y have 1 and 7 electrons in their outermost shell respectively.

Which element will lose electron?

Additional questions | Q 6.2

Elements X and Y have 1 and 7 electrons in their outermost shell respectively.

Which element will gain electron?

Additional questions | Q 6.3

Elements X and Y have 1 and 7 electrons in their outermost shell respectively.

Which will form positive ion?

Additional questions | Q 6.4

Elements X and Y have 1 and 7 electrons in their outermost shell respectively.

Which will form negative ion?

Additional questions | Q 6.5

Elements X and Y have 1 and 7 electrons in their outermost shell respectively.

What will be the charge present of the molecule XY after chemical combination?

Additional questions | Q 7.1

What is the number of electrons donated by a magnesium atom and number of electrons accepted by a sulphur atom during their chemical combination?

Additional questions | Q 7.2

How many units of charge are developed on each atom?

Additional questions | Q 7.3

What is the number of electrons after the transfer of electrons in magnesium and sulphur atoms.

Additional questions | Q 7.4

Diagrammatically represent the transfer of electrons.

Additional questions | Q 8

What do you understand by the following terms valency, valence electrons and valence shell?

Additional questions | Q 9

Name the following radicals and give their valencies:

1. SO4
2. CO3
3. OH4.
4.Cr2O7

Additional questions | Q 10

What is variable valency ? Give two examples of elements showing variable valency.

Additional questions | Q 11.1

Name three elements each whose ions have valency +1, +2 and +3 respectively

Additional questions | Q 11.2

Name three non-metals/radicals which have valency -1, -2, and -3.

Additional questions | Q 12.1

Define: Ionic bond

Additional questions | Q 12.2

Define: Covalent bond

Additional questions | Q 13

Give two examples for each of ionic and covalent bond.

Additional questions | Q 14

Write electronic configuration of oxygen, fluorine, sodium, silicon, argon.

Additional questions | Q 15

Who originated the word ‘atom’ ?

Additional questions | Q 16

What does the word ‘atom’ mean?

Additional questions | Q 17

State Dalton’s atomic theory.

Additional questions | Q 18

How did Neils Bohr visualise the atom ?

Additional questions | Q 19.1

Name the particle or particles you would expect to find in :

The orbit of an atom

Additional questions | Q 19.2

Name the particle or particles you would expect to find in :

The nucleus of an atom

Additional questions | Q 20.1

An atom has 13 protons and 14 neutrons.

What is the atomic number of the atom ?

Additional questions | Q 20.2

An atom has 13 protons and 14 neutrons.

How many electrons would be present in this atom ?

Additional questions | Q 20.3

An atom has 13 protons and 14 neutrons.

What is the atomic mass of the atom ?

Additional questions | Q 21.1

Define: An Atom:

Additional questions | Q 21.2

Define: Atomic number

Additional questions | Q 21.3

Define: Mass number :

Additional questions | Q 21.4

Define: Atomic weight :

Additional questions | Q 22.1

A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.

What is such a particle called ?

Additional questions | Q 22.2

A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.

What is the mass number of X ?

Additional questions | Q 22.3

A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.

What is the atomic numebr of X ?

Additional questions | Q 22.4

A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.

Does the particle have an excess of electrons or a deficiency of electrons ?

Additional questions | Q 22.5

A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.

What is the charge on the particle ?

Additional questions | Q 23.1

Fill in the blank

If an atom gains an electron, it is called an _______

Additional questions | Q 23.2

Fill in the blank

If an atom loses an electron, it acquires ______ a charge.

Additional questions | Q 23.3

Fill in the blank

A charged particle is called an _____

Additional questions | Q 23.4

Fill in the blank

An _______ is electrically neutral.

Additional questions | Q 23.5

Fill in the blank

An excess of electrons produces a ________ charge.

Additional questions | Q 23.6

Fill in the blank

A deficiency of electrons produces a ________ charge.

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## Chapter 4: Atoms, Molecules and Radicals

ExerciseObjective type questionsAdditional questions

## Selina solutions for Concise Chemistry Class 7 ICSE chapter 4 - Atoms, Molecules and Radicals

Selina solutions for Concise Chemistry Class 7 ICSE chapter 4 (Atoms, Molecules and Radicals) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE Concise Chemistry Class 7 ICSE solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com provide such solutions so that students can prepare for written exams. Selina textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Concise Chemistry Class 7 ICSE chapter 4 Atoms, Molecules and Radicals are Naming Chemical Compounds, Atoms: Building Blocks of Matter, Molecules, Dalton’s atomic theory, Classification of Molecules, Classification of Molecules, Molecular Formula of an Elements, Classification of Molecules, Radicals and Its Types, Difference Between Atom, Molecules, and Radicals, Valency, Variable Valency, The Modern Periodic Table, Molecular Formula of an Compounds, Chemical Formula Or Molecular Formula.

Using Selina Class 7 solutions Atoms, Molecules and Radicals exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Selina Solutions are important questions that can be asked in the final exam. Maximum students of CISCE Class 7 prefer Selina Textbook Solutions to score more in exam.

Get the free view of chapter 4 Atoms, Molecules and Radicals Class 7 extra questions for Concise Chemistry Class 7 ICSE and can use Shaalaa.com to keep it handy for your exam preparation

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