NCERT Solutions Class 10 Science Chapter 5 Life Processes

Life Processes are the basic maintenance activities that keep living organisms alive.
NCERT Solutions Class 10 Science Chapter 5 connect this chapter with nutrition, respiration, transportation and excretion.

Chapter 5 Life Processes explains how living organisms obtain energy, use food, exchange gases, transport materials and remove wastes. It begins with the idea that living beings need continuous molecular movement and maintenance even when they are not visibly active.

NCERT Solutions for Class 10 Science Chapter 5 - All Exercise Questions

Life Processes
Easy
Q.
The kidneys in human beings are a part of the system for
(a) nutrition.
(b) respiration.
(c) excretion.
(d) transportation.
Life Processes
Easy
Q.
The xylem in plants are responsible for
  1. transport of water.
  2. transport of food.
  3. transport of amino acids.
  4. transport of oxygen.
Life Processes
Easy
Q.
The autotrophic mode of nutrition requires
  1. carbon dioxide and water.
  2. chlorophyll.
  3. sunlight.
  4. all of the above.
Life Processes
Easy
Q.
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
  1. cytoplasm.      
  2. mitochondria.
  3. chloroplast.
  4. nucleus.
Life Processes
Easy
Q.
How are fats digested in our bodies? Where does this process take place?
Life Processes
Easy
Q.
What is the role of saliva in the digestion of the food?
Life Processes
Medium
Q.
What are the necessary conditions for autotrophic nutrition and what are its by products?
Life Processes
Easy
Q.
What are the differences between aerobic and anaerobic respiration. Name some organisms that use the anaerobic mode of respiration.
Life Processes
Easy
Q.
How are the alveoli designed to maximise the exchange of gases?
Life Processes
Easy
Q.
What would be the consequences of a deficiency of haemoglobin in our bodies?
Life Processes
Medium
Q.
Describe double circulation in human beings. Why is it necessary?
Life Processes
Medium
Q.
What are the differences between the transport of materials in xylem and phloem?
Life Processes
Medium
Q.
Compare the functioning of alveoli in lungs and nephrons in the kidneys with respect to their structure and functioning.

NCERT Solutions Class 10 Science Chapter 5 cover all exercise questions in textbook order, including Life Processes Class 10, nutrition in human beings Class 10, autotrophic nutrition Class 10, aerobic and anaerobic respiration Class 10, human respiratory system Class 10, transportation in human beings Class 10, transportation in plants Class 10, excretion in human beings Class 10, and Class 10 Science life processes solutions for revision. The chapter identifies nutrition, respiration, transportation and excretion as essential life processes.

Key Takeaways

  • Nutrition: Organisms obtain food and raw materials for energy, growth and repair.
  • Respiration: Food is broken down to release energy, usually in the form of ATP.
  • Transportation: Materials such as oxygen, food, water and wastes are moved within the body.
  • Excretion: Harmful metabolic wastes are removed from the body.

NCERT Solutions Class 10 Science Chapter 5 Structure 2026

Section Main Topic Question Focus
5.1 What are life processes? Maintenance, energy, raw materials
5.2 Nutrition Autotrophic nutrition, human digestion
5.3 Respiration Aerobic and anaerobic respiration, lungs
5.4 Transportation Heart, blood, xylem and phloem
5.5 Excretion Nephrons, urine formation, plant wastes
Exercises NCERT questions 13 textbook questions

NCERT Class 10 Science Chapter 5 Exercise Solutions

The exercise questions in Chapter 5 test whether students understand digestion, photosynthesis, respiration, blood circulation, transport in plants, kidney function and the comparison between alveoli and nephrons.

Life Processes Class 10: Exercise Questions and Answers

Q1. The kidneys in human beings are a part of the system for:

Options:

(a) nutrition
(b) respiration
(c) excretion
(d) transportation

Kidneys remove nitrogenous wastes such as urea from the blood and help form urine.

Answer:

(c) excretion

Q2. The xylem in plants are responsible for:

Options:

(a) transport of water
(b) transport of food
(c) transport of amino acids
(d) transport of oxygen

Xylem transports water and minerals from roots to other parts of the plant.

Answer:

(a) transport of water

Q3. The autotrophic mode of nutrition requires:

Options:

(a) carbon dioxide and water
(b) chlorophyll
(c) sunlight
(d) all of the above

Autotrophic nutrition needs carbon dioxide, water, chlorophyll and sunlight for photosynthesis.

Answer:

(d) all of the above

Q4. The breakdown of pyruvate to give carbon dioxide, water and energy takes place in:

Options:

(a) cytoplasm
(b) mitochondria
(c) chloroplast
(d) nucleus

In aerobic respiration, pyruvate is broken down in mitochondria to form carbon dioxide, water and energy. The chapter explains that glucose first breaks into pyruvate in the cytoplasm, and pyruvate is then broken down using oxygen in mitochondria.

Answer:

(b) mitochondria

Nutrition in Human Beings Class 10

Q5. How are fats digested in our bodies? Where does this process take place?

Fats are digested mainly in the small intestine.

Fats reach the small intestine in the form of large globules. These large globules are difficult for enzymes to act upon. Bile salts from the liver break the large fat globules into smaller globules. This process is called emulsification.

After emulsification, pancreatic juice acts on fats. The enzyme lipase breaks down emulsified fats into fatty acids and glycerol. The intestinal juice also helps complete digestion.

Answer:

Fats are digested in the small intestine. Bile salts emulsify fats into smaller globules, and lipase breaks them down into fatty acids and glycerol.

Q6. What is the role of saliva in the digestion of food?

Saliva helps in digestion in two ways.

First, it wets the food and makes it easier to chew and swallow. This helps the food move smoothly through the food pipe.

Second, saliva contains the enzyme salivary amylase. This enzyme begins the digestion of starch in the mouth by breaking starch into simple sugars.

Answer:

Saliva moistens food and contains salivary amylase, which breaks down starch into simple sugars.

Autotrophic Nutrition Class 10

Q7. What are the necessary conditions for autotrophic nutrition and what are its by-products?

Autotrophic nutrition takes place through photosynthesis.

Necessary conditions:

Carbon dioxide

Water

Chlorophyll

Sunlight

During photosynthesis, plants use carbon dioxide and water in the presence of sunlight and chlorophyll to make carbohydrates. Oxygen is released as a by-product.

Copy-friendly equation:

6CO₂ + 12H₂O — sunlight/chlorophyll → C₆H₁₂O₆ + 6O₂ + 6H₂O

Answer:

Autotrophic nutrition requires carbon dioxide, water, chlorophyll and sunlight. Its main product is carbohydrate, and oxygen is released as a by-product.

Aerobic and Anaerobic Respiration Class 10

Q8. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Aerobic Respiration Anaerobic Respiration
Takes place in the presence of oxygen Takes place in the absence of oxygen
Produces carbon dioxide, water and energy Produces ethanol and carbon dioxide in yeast, or lactic acid in muscles
Releases more energy Releases less energy
Takes place mainly in mitochondria after glycolysis Takes place in cytoplasm

Examples of organisms using anaerobic respiration:

Yeast

Some bacteria

Anaerobic respiration also occurs in human muscle cells during sudden activity when oxygen is insufficient. The chapter explains that yeast converts pyruvate into ethanol and carbon dioxide during fermentation, while muscle cells may form lactic acid when oxygen is lacking.

Answer:

Aerobic respiration uses oxygen and releases more energy. Anaerobic respiration occurs without oxygen and releases less energy. Yeast and some bacteria use anaerobic respiration.

Human Respiratory System Class 10

Q9. How are the alveoli designed to maximise the exchange of gases?

Alveoli are tiny balloon-like structures present at the end of the respiratory tubes in the lungs.

They are designed for efficient gas exchange because:

They provide a large surface area.

Their walls are thin and delicate.

They are surrounded by a rich network of blood capillaries.

Oxygen from alveolar air diffuses into the blood.

Carbon dioxide from blood diffuses into the alveoli.

The lungs also contain residual air, which gives enough time for oxygen to be absorbed and carbon dioxide to be released. The chapter states that alveoli provide the surface where exchange of gases takes place and that their walls contain an extensive network of blood vessels.

Answer:

Alveoli have thin walls, a large surface area and many blood capillaries, which together maximise gas exchange.

Q10. What would be the consequences of a deficiency of haemoglobin in our bodies?

Haemoglobin is the respiratory pigment present in red blood corpuscles. It carries oxygen from the lungs to body tissues.

If haemoglobin is deficient:

Less oxygen will be transported to body cells.

Cells will receive less oxygen for respiration.

Less energy will be released.

The person may feel tired, weak and breathless.

Body activities may slow down because of poor oxygen supply.

Answer:

A deficiency of haemoglobin reduces oxygen transport in the body, causing weakness, tiredness and lower energy release in cells.

Transportation in Human Beings Class 10

Q11. Describe double circulation of blood in human beings. Why is it necessary?

Double circulation means that blood passes through the heart twice in one complete cycle of circulation.

There are two parts:

Pulmonary circulation:

Deoxygenated blood from the right side of the heart goes to the lungs.

In the lungs, carbon dioxide is removed and oxygen is added.

Oxygenated blood returns to the left side of the heart.

Systemic circulation:

Oxygenated blood from the left side of the heart is pumped to the body.

Body cells use oxygen and return deoxygenated blood to the right side of the heart.

Double circulation is necessary because it keeps oxygenated and deoxygenated blood separate. This helps the body receive a highly efficient supply of oxygen. It is especially important for mammals and birds because they need high energy to maintain body temperature. The chapter explains that separation of the right and left sides of the heart prevents mixing of oxygen-rich and carbon dioxide-rich blood.

Answer:

Double circulation is the movement of blood through the heart twice in one cycle: once between heart and lungs, and once between heart and body. It is necessary to keep oxygenated and deoxygenated blood separate for efficient oxygen supply.

Transportation in Plants Class 10

Q12. What are the differences between the transport of materials in xylem and phloem?

Xylem Phloem
Transports water and minerals Transports food and other soluble products
Movement is mainly upward from roots to leaves Movement can be upward and downward
Transport depends mainly on root pressure and transpiration pull Transport uses energy from ATP
Made of vessels and tracheids Made of sieve tubes and companion cells
Mostly transports raw materials Mostly transports products of photosynthesis

The chapter explains that xylem moves water and minerals from the soil, while phloem transports products of photosynthesis from leaves to other parts of the plant. It also states that phloem transport, called translocation, uses energy from ATP.

Answer:

Xylem transports water and minerals mainly upward, while phloem transports food and other substances in both upward and downward directions using energy.

Excretion in Human Beings Class 10

Q13. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.

Point of Comparison Alveoli Nephrons
Organ Lungs Kidneys
Structure Balloon-like sacs with thin walls Filtration units made of Bowman’s capsule, capillaries and tubules
Blood Supply Surrounded by blood capillaries Contains a cluster of blood capillaries
Main Function Exchange of gases Filtration of blood and urine formation
Material Removed Carbon dioxide from blood Nitrogenous wastes such as urea
Material Taken Back Oxygen enters blood Useful substances such as glucose, amino acids, salts and water are reabsorbed
Final Output Carbon dioxide-rich air is exhaled Urine is formed

Alveoli and nephrons both have thin-walled structures closely associated with blood capillaries. Alveoli help exchange oxygen and carbon dioxide. Nephrons filter blood, reabsorb useful substances and remove wastes through urine. The chapter explains that each nephron has a cup-shaped Bowman’s capsule with a capillary cluster and that useful substances such as glucose, amino acids, salts and water are selectively reabsorbed as urine flows along the tube.

Answer:

Alveoli are gas-exchange units of lungs, while nephrons are filtration units of kidneys. Both have thin walls and rich blood supply, but alveoli exchange gases and nephrons remove nitrogenous wastes from blood.

Life Processes Class 10: Concepts Used in Chapter 5

Chapter 5 Life Processes includes nutrition, respiration, transportation and excretion. These processes maintain life by supplying energy, moving materials and removing wastes.

Life Processes Class 10

Life processes are the maintenance functions that continue in living organisms even when they are resting.

Examples:

Nutrition

Respiration

Transportation

Excretion

Nutrition in Human Beings Class 10

Nutrition in human beings takes place through the alimentary canal.

Main steps:

Ingestion

Digestion

Absorption

Assimilation

Egestion

Important organs:

Mouth

Oesophagus

Stomach

Small intestine

Large intestine

Anus

Autotrophic Nutrition Class 10

Autotrophic nutrition is the mode of nutrition in which organisms make their own food from simple inorganic substances.

Main process:

Photosynthesis

Raw materials:

Carbon dioxide

Water

Sunlight

Chlorophyll

Aerobic and Anaerobic Respiration Class 10

Respiration releases energy from food.

Aerobic respiration:

Glucose is broken down using oxygen.

Products:

Carbon dioxide, water and energy

Anaerobic respiration:

Glucose is broken down without oxygen.

Products in yeast:

Ethanol, carbon dioxide and energy

Product in muscles during oxygen shortage:

Lactic acid

Human Respiratory System Class 10

Main parts:

Nostrils

Nasal passage

Trachea

Bronchi

Bronchioles

Alveoli

Lungs

Function:

It helps take oxygen into the body and remove carbon dioxide.

Transportation in Human Beings Class 10

The transport system in human beings consists of:

Heart

Blood

Blood vessels

Blood transports:

Oxygen

Carbon dioxide

Digested food

Nitrogenous wastes

Salts and other substances

Transportation in Plants Class 10

Plants use vascular tissues for transport.

Xylem:

Transports water and minerals.

Phloem:

Transports food and other soluble products.

Excretion in Human Beings Class 10

The human excretory system includes:

A pair of kidneys

A pair of ureters

Urinary bladder

Urethra

The kidney’s basic filtration unit is called the nephron.

Quick Revision Table for NCERT Solutions Class 10 Science Chapter 5

Concept Copy-Friendly Point Used In
Life processes Nutrition, respiration, transportation, excretion Full chapter
Photosynthesis 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O Q7
Aerobic respiration Uses oxygen and releases more energy Q8
Anaerobic respiration Occurs without oxygen and releases less energy Q8
Alveoli Gas exchange surface in lungs Q9, Q13
Haemoglobin Transports oxygen in blood Q10
Double circulation Blood passes through heart twice in one cycle Q11
Xylem Transports water and minerals Q12
Phloem Transports food using energy Q12
Nephron Filtration unit of kidney Q13

Useful Links for Class 10 Science NCERT Solutions

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Class 10 Science NCERT Solutions NCERT Solutions for Class 10 Science
Chapter 1 NCERT Solutions for Class 10 Science Chapter 1
Chapter 2 NCERT Solutions for Class 10 Science Chapter 2
Chapter 3 NCERT Solutions for Class 10 Science Chapter 3
Chapter 4 NCERT Solutions for Class 10 Science Chapter 4
Chapter 5 NCERT Solutions for Class 10 Science Chapter 5
Chapter 6 NCERT Solutions for Class 10 Science Chapter 6
Chapter 7 NCERT Solutions for Class 10 Science Chapter 7
Chapter 8 NCERT Solutions for Class 10 Science Chapter 8
Chapter 9 NCERT Solutions for Class 10 Science Chapter 9
Chapter 10 NCERT Solutions for Class 10 Science Chapter 10
Chapter 11 NCERT Solutions for Class 10 Science Chapter 11
Chapter 12 NCERT Solutions for Class 10 Science Chapter 12
Chapter 13 NCERT Solutions for Class 10 Science Chapter 13
Chapter 14 NCERT Solutions for Class 10 Science Chapter 14

Q.1 Atomic number of an element is 19.
(i) Is it a metal or non-metal?
(ii) Will the size of this element be greater than that of sodium?

(i) The electronic configuration of the given element is 2,8,8,1. Therefore, it has 1 electron in the valence shell. Hence, it is a metal.
(ii) The element with atomic number 19 is potassium. Since it is placed below sodium in periodic table, it is larger in size as compared to sodium.

Q.2 What change will be observed in atomic size when we move from top to bottom in group 2. Give reasons also.

As we move from top to bottom in a group, new shells are being added and the distance between the nucleus and the outermost shell goes on increasing and size of the atom increases. Therefore, when we move down in group 2, the size of atom increases.

Q.3 An element (X) belongs to second period and first group of the periodic table. Find:
(i) the number of valence electrons present in its atom.
(ii) the valency of the element.
(iii) whether element (X) forms acidic or basic oxide.

(i) The number of valence electrons in element X is one (because it belongs to group 1).
(ii) As element X has one electron in outermost shell, its valency is one.
(iii) Since element (X) belongs to group one, it is a metal. It will form basic oxide.

Q.4 When a metal M reacts with a non-metal X, it forms a compound of MX type.

(a) Identify the group in which element M and X are placed in modern periodic table.
(b) Write the number of valence electrons present in element M and element X.
(c) Write an example of MX type of compound.

(a) The metal M belongs to group1 (alkali metals) and X belongs to group 17 (Halogen group).
(b) The number of valence electrons present in M is one and the mumber of valence electrons present in X is 7.
(c) NaCl or KCl

Q.5 Element P belongs to group 2 of modern periodic table and element Q belongs to group 17 of modern periodic table. Write the formula of:

(i) the compound formed by elements P and Q.
(ii) the oxide of element P.
(iii) the chloride of element P.

(i)The valency of element P is 2 (because it belongs to group 2) and that of element Q is 1 (because it belongs to group 17). The formula of compound will be PQ2.
(ii) PO
(iii) PCl2

Q.6 What was the drawback of the law of octaves?

The law of octaves was applicable only upto calcium out of the total 56 elements known.

Q.7 The positions of three elements A, B, and C in the periodic table are shown here.

Group 16 Group 17
– –
– A
– –
B C

(a) State whether A is a metal or non-metal
(b) State whether C is more reactive or less reactive than A.
(c) Will C be larger or smaller in size than B?

(a) The group 17 is placed in right hand side of the periodic where non-metals are placed. So, A is a non-metal.
(b) The chemically reactivity of non-metals decreases on going down the group of the periodic table. So, C is less reactive than A.
(c) On going from left to right in a period, the atomic radii decreases. So, C is smaller than B.

Q.8 By considering their position in the periodic table, which one of the following elements would you except to have the maximum metallic character?
C , O, F, B, Be

The maximum metallic character is found in elements on the extreme left side of the periodic table. Out of the above given elements, Be will have the maximum metallic character because it is on the extreme left side in the periodic table.

Q.9 What does each period in the periodic table indicate?

Each period in the periodic table indicates the number of shells.

Q.10 An atom has electronic configuration 2, 8, 7:-
(a) What is the atomic number of this element?
(b) To which of the following elements would it be chemically similar?
N (7), F (9), P (15), Ar (18).

(a) Atomic number of this element is 17.
(b) F will chemically be similar to this element because F has similar valence electrons.

Q.11 Name two elements you would choose to show chemical reactions similar to magnesium. Write the basis for your choice?

Calcium and Strontium would show chemical reactions similar to magnesium because they have same number of valence electrons like Mg.

Q.12 Write the characteristics of the groups.

Characteristics of the groups are: –
(i) Valence Electrons: – All the elements of a group of the periodic table have the same number of valence electrons.
(ii) Size of Atoms: – On moving down the group atomic size of the atom increases due to increase in number of shells.
(iii) Metallic Character: – On moving down the group metallic character of elements increases.
(iv) Valency: – Since the number of valence electrons in a group is the same, so all the elements in a group have the same valency.
(v) Non-metallic Character: – On moving down the group non-metallic character of elements decreases.

Q.13 Write the merits of the modern periodic table.

Merits of the modern periodic table are: –
1.It is based on the atomic number of elements which is the most fundamental property of elements.
2. It explains the reason for the periodicity in properties of elements.
3. It helps us understand why elements in a group show similar properties but elements in different groups show different properties.
4. It tells us why the properties of elements are repeated after 2, 8, 18 and 32 elements. There are no anomalies in the arrangement of elements in the modern periodic table.

Q.14 Consider the following elements:Na, Ca, Al, K, Mg, Li
(a) Which of these elements belong to the same period of the periodic table?
(b) Which of these elements belong to the same group of the periodic table?

The electronic configurations of the following elements are:
Na: – 2, 8, 1
Ca: – 2, 8, 8, 2
Al: – 2, 8, 3
K: – 2, 8, 8, 1
Mg: – 2, 8, 2
Li: – 2, 1
(a) Na, Al and Mg elements belong to third period and Ca and K elements belong to the fourth period of the periodic table because Na, Al and Mg elements have same number of shell (three shells) and Ca and K elements have same number of shells(four shells).
(b)The elements which have same number of valence electrons belong to the same group. So, Li, Na and K having 1 valence electron belong same group and Mg, Ca having 2 valence electrons belong same group.

Q.15 Write the limitations of Mendeleev’s classification of elements.

1. The position of isotopes could not be explained.
2. Wrong order of atomic masses of some elements could not be explained.
3. Correct position could not be assigned to hydrogen in the periodic table.

Q.16 For each the following triads, name the element with the characteristics specified below:

Elements Smallest atomic radius Chemically least reactive
F, Cl, Br ………….. ……………
Li, Na, K …………… …………….

Ans-

Elements Smallest atomic radius Chemically least reactive
F, Cl, Br F Br
Li, Na, K Li Li

Q.17 Write the merits of Mendeleev’s classification of elements.

Merits of Mendeleev’s classification of elements:
1. Mendeleev’s classification was first successful classification of elements which included all the elements.
2. It predicted the properties of elements which were not known at that time.
3. When noble gases were discovered, they could be placed in a new group without disturbing the existing order.

Q.18 Write the demerits of Newlands’ law of octaves.

Demerits of Newlands’ law of octaves: –
(i) This law was applicable upto calcium only.
(ii) Newlands’ assumed that only 56 elements existed in nature and no more elements would be discovered in future.
(iii) In order to fit elements into his table, Newland put even two elements together in one slot and that too in the column of unlike elements having very different properties.

Q.19 What are the advantages of the periodic table?

1. The periodic table has made the study of chemistry systematic and easy.
2. It is easier to remember the properties of an element if its position in the periodic table is known.
3. The type of compounds formed by an element can be predicted by knowing its position in the periodic table.

Q.20 An element X belongs to group 2 and another element Y belongs to group 15 of the periodic table:-

(a) What is the number of valence electrons in X?
(b) What is the valency of X?
(c) What is the number of valence electrons in Y?
(d) What is the valency of Y?

Ans-

(a) Valence electrons of X = 2
(b) Valency of X = 2
(c) Valence electrons of Y = 5
(d) Valency of Y = 3

Q.21 What happens to

(i) Metallic character of the elements as we move from left to right in a period.
(ii) Atomic size when we move from top to bottom in a group.

Ans-

(i) When we move left to right in a period metallic character decreases.
(ii) Atomic size increases when we move from top to bottom in a group.

Q.22 Explain why?

(i) All the elements of a group have similar chemical properties.
(ii) All the elements of a period have different chemical properties.

Ans- Chemical properties of the elements depend upon the valence electrons, it means the elements which have the same number of valence electrons in their outermost shells, will have similar chemical properties.
(i) So all the elements of the group have similar chemical properties owing to the same number of valence electrons.
(ii) But the elements of a period have different valencies, hence they show different chemical properties.

Q.23 Element X forms a chloride XCl2, which is a solid with a high melting point. X would most likely be in the same group of the periodic table as:
(a) Na (b) Mg (c) Al (d) Si

Ans- Since element X forms a chloride XCl2, so the valency of X is 2. Now, out of Na, Mg, Al, and Si, the element of valency 2 is Mg. So, X would be in the same group as that of Mg because all the elements of the same group have same valency.

Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the periodic table. Write the electronic configuration of these two elements. Which of these will be more electronegative. Why?

Ans- Electronic configuration of Nitrogen is 2, 5.

Electronic configuration of Phosphorus is 2, 8, 5.
Nitrogen is more electronegative than phosphorus due to its small size.

Q.25 How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

Ans- The properties of the elements depend upon the valence electrons. On arranging the elements in the increasing order of their atomic numbers, the elements with the same number of valence electrons and hence, showing similar properties occur at regular intervals. Hence, the chemical properties of the elements show repetition.

Q.26Out of F and Cl, which is bigger in size and why?

Ans- Fluorine and chlorine belong to same group. When we move down the group the size of atom increases due to increase in number of shells. Therefore, the size of chlorine atom will be larger as compared to the atom of chlorine.

Q.27 Write the electronic configuration of Ca in terms of K, L, M, N shells.

(Atomic number of Ca is 20)

Ans- The electronic configuration of Ca is

K L M N
2 8 8 2

Q.28 Define groups.

Ans- The vertical columns in the long form of the periodic table are called groups.

Q.29 In the Modern Periodic Table, which are the metals among the first ten elements?

Ans- Li and Be are the metals amongst first ten elements of the Modern Periodic Table.

Q.30 Which period is the longest period in the modern periodic table?

Ans- 6th period is the longest period and it has 32 elements.

Q.31 In the following diagram for the first three periods (showing only group 1,2, 13 to 18)of the periodic table, five elements have been represented by the letters a, b, c, d and e (which are not their chemical symbols):

(i) Select the letter which represents a halogen.
(ii) Select the letter which represents a noble gas.
(iii) What type of bond is formed between a and b?
(iv) What type of bond is formed between c and d?
(v) Which element will form a divalent anion?

Ans-

(i) The halogens are placed in group 17 of the periodic table. So, letter ‘b’ represents a halogen.
(ii) The noble gases are placed in group 18 of the periodic table. So, letter ‘e’ represents a noble gas.
(iii) ‘a’ and ‘b’ both are non-metals. So, the bond formed in between ‘a’ and ‘b’ will be covalent.
(iv) ‘c’ is metal and ‘d’ is non-metal. So, the bond formed in between ‘c’ and ‘d’ will be electrovalent.
(v) ‘d’ element will form a divalent anion because it has 6 valence electrons and it wants to 2 more electrons to completes its octet.

Q.32 What is the basis of classification of elements?

Ans- Elements are classified on the basis of similarities in their properties.

Q.33 How many periods are present in Modern periodic table?

Ans- Seven periods are present in the modern periodic table.

Q.34 Besides gallium, which other elements have been since discovered to fill the gaps left by Mendeleev in his periodic table? (Any two)

Ans- Eka-boron (Scandium) and Eka-silicon (Germanium)

Q.35 What is the fundamental difference in the electronic configuration of the group I and group II elements?

Ans- Group I elements have 1 electron in their outermost shell whereas group II elements have 2 electrons in their outermost shell.

Q.36 How many groups are in the long form of the periodic table?

Ans- There are 18 vertical columns called groups in the long form of periodic table.

Q.37 State the modern periodic law.

Ans- According to the modern periodic law the properties of elements are periodic function of their atomic numbers.

Q.38 What was the criteria used by Mendeleev in creating his periodic table?

Ans- Mendeleev used atomic mass of the elements as the criteria to create his periodic table.

Q.39 What was the main limitation of Dobereiner’s triad?

Ans- Dobereiner’s classification failed to arrange all the known elements in the form of triads of elements having similar chemical properties.

Q.40 Why do you think the noble gases are placed in a separate group?

Ans- Noble gases are placed in a separate group because all of them have completely filled shells. Therefore, these gases are inert in nature and do not generally participate in any chemical reaction.

Q.41 An element ‘X’ belongs to second period and second group of the periodic table.
Find:
(i) the number of valence electrons.
(ii) the valency of the element.
(iii) whether element X forms acidic or basic oxide.

Ans-

(i) Group number of element = Number of valence electrons
Therefore, number of valence electrons will be 2.
(ii) The valency of elements will be 2.
(iii) Nature of its oxide will be basic because it is a metal.

Q.42 Write the names of
(a) two elements that have seven electrons in their outermost shells
(b) two elements that have two electrons in their outermost shells
(c) two elements which have completely filled outermost shells

Ans-

(a) Chlorine (Cl) and Bromine (Br)
(b) Magnesium (Mg) and Calcium (Ca)
(c) Neon (Ne) and Argon (Ar)

Q.43 How many elements were known when Mendeleev classified the elements?

Ans- At the time of Mendeleev, 63 elements were known.

Q.44 Why are the elements in the same group of the periodic table show close resemblance in chemical behaviour?

Ans- The elements in the same group of the periodic table show close resemblance in their chemical behaviour as they have the same number of valence electrons.

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FAQs (Frequently Asked Questions)

NCERT Solutions Class 10 Science Chapter 5 cover Life Processes, including nutrition, respiration, transportation and excretion in plants and animals.

The main life processes are nutrition, respiration, transportation and excretion.

Fats are digested in the small intestine. Bile salts emulsify fats, and lipase breaks them into fatty acids and glycerol.

Aerobic respiration takes place in the presence of oxygen and releases more energy. Anaerobic respiration takes place without oxygen and releases less energy.

Xylem transports water and minerals from roots to other parts of the plant. Phloem transports food and other soluble products from leaves to different parts of the plant.