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Answer: The first ten elements in modern periodic table are hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and neon. Out of these, lithium, beryllium and boron are metals, because they have 1, 2 and 3 electrons respectively in their outermost shells. Question 6 By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristics?

In the periodic table, the elements placed Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year on the left show maximum metallic characteristics. Since beryllium occupies the most left position in comparison to other elements, hence it shows maximum metallic characteristics.

Question 1 Which of the following statements is not a correct statement about the trends wlien going from left to Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year right across the periods of Periodic Table. Answer: c The atoms lose their. Question 2 Element X forms a chloride with the formula XCl 2 , which is solid with a high melting point. Question 3 Which element has a two shells, both of which are For Year Solutions Ncert Science 10th Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year completely filled with electrons? Question 4 a What property do all elements in the same column of the Periodic Table as boron have in common?

Answer: a Elements in the same column or group as boron have valency of three and have three valence electrons. Question Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year 5 An atom has electronic configuration 2, 8, 7. Atomic numbers are given in parentheses. Question 6 The positions of three elements A, B and C in the periodic table are shown below : a State whether A is a metal or non-metal. Answer: a Since Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year the valency of group 17 elements is 1 and all these elements accept electrons, thus A is a non-metal. Question 7 Nitrogen atomic number 7 and phosphorus atomic number 15 belong to group 15 of the periodic table.

Write the electronic configuration of these two Ncert Solutions For 10th Science Year elements. Which of these will be more electronegative? In a group of the periodic table, electron attracting tendency decreases as we move from top to bottom. Question 8 How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?Ncert Solutions For 10th Science Year

Answer: Modern periodic table is based on the atomic number and atomic number is directly related to the electronic configuration. One can find the group number and period number of an element on the basis of electronic configuration. For example, if an element has 1 or Ncert Solutions For 10th Science Year 2 electrons in its outermost shell, then it would belong to group 1 or group 2.

And if it has 3 or more electrons in its outermost shell, then it would belong to group 10 4- the number of electrons in the outermost shell. All Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Solutions Ncert For 10th Year Science the alkali metals have one electron in their outermost shell, so they are placed in group 1. Thus, all the group 2 elements have 2 electrons in their outermost shell. In group 15 elements, there are 5 electrons in their outermost shell.

Similarly, the number Ncert Solutions For 10th Science Year of shells in an element indicates its period number. For example, the atomic number of magnesium is 12 and its electronic configuration is 2, 8, 2. Thus it is an element of 3rd period. Question 9 In the Modern Periodic Table, calcium atomic number 20 Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year is surrounded by elements with atomic number 12, 19, 21 and Which of these have physical and chemical properties resembling calcium? Periodic classification of elements: Needs for classification, Modern Periodic table, gradation in properties, valency, atomic number, metallic and non-metallic properties.

Formulae Handbook for Class 10 Ncert Solutions For 10th Science Year Maths and Science. Solution: All the known elements could not be arranged in the form of triads. Take the example of F, Cl and Br. Atomic mass of Cl is not an arithmetic mean of atomic masses of F and Br. Solution: It was not valid for elements that had atomic masses higher than Ca. When more elements were discovered, such as elements from the noble gases such as He, Ne, Ar, they could not be accommodated in his table.

Question 5 Besides gallium, which other elements have been left Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year by Mendeleev in his periodic table, since the time they were discovered? Any two Solution: Scandium and Germanium. Question 6 What were the criteria used by Mendeleev in creating his periodic table? Solution: He observed the relationship between the atomic masses of the elements and Ncert Solutions For 10th Science Year their physical properties.

Among chemical properties, he concentrated on the compounds formed by elements with oxygen and hydrogen. Question 7 Why do you think, the noble gases are placed in a separate group? Solution: Due to its inert and low concentration in our atmosphere, they Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year could be placed in a new group without disturbing the existing order.

For example, Position of isotopes: All the isotopes of an element have the same number of protons, so their atomic number is also the same. Since all the isotopes of an element have the same atomic number, they can be put at one place in the same group of the periodic table.

Question 9 Name two elements, which you would expect to show chemical reactions similar to magnesium. Solution: Calcium and Beryllium are the elements that will show chemical Ncert Solutions For 10th Science Year reactions similar to magnesium. This is because beryllium and calcium belong to the same group of periodic table as magnesium. All of them have similar electronic configurations with 2 valence electrons each. Question 10 Name: a.

Three elements that have a single electron in their Ncert Solutions For 10th Science Year outermost shell. Two elements that have two electrons in their outermost shell. Three elements with filled outermost shell.

Solution: a. Three elements that have a single electron in their outermost shell are: 1. Lithium 2. Sodium 3. Potassium b. Two elements that have two electrons Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year in their outermost shell are: 1. Magnesium 2. Calcium c. Three elements with filled outermost shell are: 1.

Argon 2. Helium 3. Question 11 a. Lithium, sodium, potassium are metals that react with water to liberate hydrogen. Helium is an unreactive gas and neon is a Ncert Solutions For 10th Science Year gas of extremely low reactivity. What, if anything, do their atoms have in common Solution: a. These elements are alkali metals and they have 1 valence electron in their outermost shell and are therefore very unstable and reactive.

These elements each have full outermost subshell, Ncert Solutions For 10th Science Year which results in high stability. They only react with other elements in extreme circumstances, the trait for which they are named. Question 12 In the Modern periodic table, which are the metals among the first ten elements? Solution: The metals are Ncert Solutions For Class 10th Science In Hindi Medium Pdf Lithium and Beryllium. Question 13 By considering their position in the periodic table, which one of the following elements would you expect to have maximum metallic characteristic?

Question 14 Which of the following statements is not a correct statement about the trends when going from left to right across the periods of the periodic table?

Question 15 Element X forms a chloride with the formula XCl 2 , which is a solid with a high melting point. X would most likely be in the same group of the periodic table as a. Si Solution: b. Question Ncert Solutions For 10th Science Year 16 Which element has? Two shells, both of which are completely filled with electrons? The electronic configuration of 2,8,2? A total of three shells, with four electrons in its valence shell? A total of two shells, with three electrons in its valence shell? Twice as many electrons in its second shell, as in its first shell?

Neon 2,8 b. Magnesium 2,8,2 c. Silicon 2,8,4 d. Boron 2,3 e. Carbon 2,4. Question 17 What property do all elements in the same column of the periodic table as fluorine have in common? Solution: These elements all have 7 electrons in their outermost shells and these often exist as salts, combined with elements from the Alkali metal group.

Question 18 An atom has electronic configuration 2,8,7. What Ncert Solutions For 10th Science Year For 10th Solutions Year Science Ncert is the atomic number of this element? Question 19 Which type of ion, cation or anion, will be formed by element A? Anion will be formed by element A. Question 20 Nitrogen atomic number 7 and phosphorus atomic number 15 belong to group 15 of Solutions 10th Ncert For Year Science the periodic Table.

Solution: Electronic configuration � Nitrogen � 2s 2 2p 3 and Phosphorus � 1s 2 2s 2 2p 6 3s 2 3p 3. Nitrogen will be more electronegative; this is because its atom has small size due to which the attraction of its Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year nucleus for the incoming electron is more. Question 21 How does the electronic configuration of an atom relate to its position in the Modern periodic table?

Solution: The electronic configuration of an atom increases in the outermost valence shell which relates to its position in Ncert Solutions For 10th Science Year Solutions Science Ncert For 10th Year Ncert Solutions For 10th Science Year the Modern periodic table. Question 22 In the Modern periodic table, calcium atomic number 20 is surrounded by elements with atomic numbers 12, 19, 21 and Solution: The atomic number of calcium is 20, so its electronic configuration is 2, 8, 8, 2.

Thus, calcium Ncert Solutions For 10th Science Year has 2 valence electrons in its outermost shell. Now, the element which has 2 valence electrons, will have physical and chemical properties resembling to that of calcium. The electronic configuration of element having atomic number 12 is 2, 8, 2. It has 2 valence electrons Ncert Solutions For 10th Science Year just like calcium. So, the element having atomic number 12 will have physical and chemical properties resembling that of calcium.

Question 23 Where do you think should hydrogen be placed in the Modern periodic table? Solution: Hydrogen element has been placed at the top of group 10th Solutions Science Year Ncert For 1, above the alkali metals because the electronic configuration of hydrogen is similar to those of alkali metals.

Question 1. Which of the following is the outermost shell for elements of 2nd period? Because in period 2, there are two shell, K and L. Question 2. An element which is an essential constituent of all organic compounds belongs to [NCERT Exemplar] a group 1 b group 14 c group 15 d group 16 Answer: b Constituent of all organic compounds is carbon. It belongs to group Question 3. Atomic number Science 10th Ncert Solutions Year For Ncert Solutions For 10th Science Year was considered to be criteria for classification. Elements with same group have same number of outermost electron.

Elements in same period have same number of outermost shell. A particular increase to decrease in certain pattern can be predicted. Many such trends are studied in this Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year chapter. Such processes are digestive system, respiration system, circulation system etc. All these things are important to leave. The thing is to consume food through digestive system, perform oxidation of food which involves the process of respiration, and transportation of food and water which is done Ncert Solutions For Ncert Solutions For Class 10th Science Chapter 3 Gre 10th Science Year through circulation.

This chapter starts with process of nutrition. The process in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. Other modes of nutrition are autotrophic and heterotrophic nutrition which are discussed in chapter. Autotrophic nutrition Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year is done by plants by photosynthesis. Heterotrophic nutrition is done by animals.

Different types of Heterotrophic nutrition are discussed. Parasitic Nutrition, saprophytic Nutrition and Holozonic Nutrition are different types of heterotrophic nutrition. Cellular nutrition is done by unicellular organisms which has been discussed in this Ncert Solutions For 10th Science Year For Year Science 10th Solutions Ncert For Ncert Solutions 10th Science Year Ncert Solutions For 10th Science Year chapter. Next topic is nutrition by human beings. It starts with mouths which include salivary glands, tongue and teeth.

The food goes to stomach through oesophagus. The food goes to stomach. Liver secretes greenish yellow liquid called bile juice.

Pancreas lies behind the lower portion Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year of stomach. It secretes pancreatic juice which contains many digestive enzymes. All such processes are discussed in this digestive system. Next is respiration. The process of respiration involves: a Gaseous exchange i. Breathing: Intake of oxygen from the atmosphere and release of CO 2.

And Ncert Solutions For 10th Science Year b Cellular respiration: Breakdown of simple food in order to release energy inside the cell. Both are discussed. The human respiration system is discussed with some special attention. Pharynx ,bronchio lungs, diaphragm are different elements of human respiratory system. Mechanisam of process involves inhale and exhale. Both Ncert Solutions For 10th Science YearNcert Solutions For 10th Science Year Ncert Solutions For 10th Science Year ong> are explained.

Circulation involves the process of transportation of food and other materials from one place to another. The blood is pumped through heart and transported through veins. So, all of them are discussed. Different components of blood are discussed-Red blood cells and White Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year blood cells. Four chambers of heart are discussed. In plants, We have discussed earlier how plants take in simple compounds such as CO 2 and photosynthesise energy stored in their chlorophyll-containing organs, namely leaves.

The other kinds of raw materials needed for building plant bodies will also have to be taken up separately. For plants, the soil is the nearest and richest source of raw materials like nitrogen, phosphorus and other minerals. The absorption of these substances therefore occurs through the part in contact with the soil, namely roots. It Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year has been discussed in details. The biological process involved in the removal of these harmful metabolic wastes from the body is called excretion.

Different organisms use varied strategies to do this. It is discussed in details for human beings. The excretory system of human beings includes Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year a pair of kidneys, a pair of ureters, an urinary bladder and urethra.

Chapter 7 - Control and Coordination System Earlier, we had started with a notion we all have, that if we see something moving, it is alive. Some of these movements are in Ncert Solutions For 10th Science Year fact the result of growth, as in plants.

A seed germinates and grows, and we can see that the seedling moves over the course of a few days, Control and coordination are the functions of the nervous system and hormones in our bodies. The responses of the nervous system can be classified as reflex action, voluntary action or involuntary action. The nervous system uses electrical impulses to transmit messages. The nervous system gets information from our sense organs and acts through our muscles.

Chemical coordination is seen in both plants Ncert Solutions For 10th Science Year and animals. Hormones produced in one part of an organism move to another part to achieve the desired effect. A feedback mechanism regulates the action of the hormones. Chapter 8 - How do organisms reproduce? Reproduction, unlike other life processes, is not essential to maintain the Ncert Solutions For 10th Science Year life of an individual organism. It involves creation of a DNA copy and additional cellular apparatus by the cell involved in the process.

Various organisms use different modes of reproduction depending on their body design such as fission, fragmentation, regeneration, budding, spore formation and vegetative Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year propagation. Sexual reproduction involves two individuals for the creation of a new individual. Modes of sexual reproduction allow for greater variation to be generated.

Reproduction in flowering plants involves transfer of pollen grains from the anther to the stigma which is referred to as pollination Ncert Solutions For 10th Science Year followed by fertilisation. The male reproductive system in human beings consists of testes which produce sperms, vas deferens, seminal vesicles, prostate gland, urethra and penis. The female reproductive system in human beings consists of ovaries, fallopian tubes, uterus and vagina. Sexual reproduction in human beings Ncert Solutions For 10th Science Year involves the introduction of sperm in the vagina of the female.

Fertilisation occurs in the fallopian tube. Chapter 9 - Heredity and Evolution We have seen that reproductive processes give rise to new individuals that are similar, but subtly different.

We have discussed how some amount of variation is produced even during asexual reproduction. Heredity and evolution deals with the fact � the long-term consequences of the accumulation of variations.

The fact of sex determination in newborn individual is completely solved. Evolution can be worked out by the study of not Science Solutions For 10th Ncert Year just living species, but also fossils. Complex organs may have evolved because of the survival advantage of even the intermediate stages. Changes in the non-reproductive tissues caused by environmental factors are not inheritable indicates about different traits like Acquired and Inherited.

Speciation may take place when variation is combined with geographical isolation. Evolutionary relationships are traced in the classification of organisms. Study of the evolution of human beings indicates that all of us belong to a single species that evolved in Africa and spread across the world in stages. Chapter Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year 10 - Light: Reflection and Refraction Light is source of energy which generates sensation of vision in human beings.

In this chapter first reflection of light is discussed. Reflection is governed by its laws. The chapter is concerned with laws of reflection. Here we are Ncert Solutions For 10th Science Year basically concerned with the spherical mirrors. After that image formation by spherical mirrors are discussed.

The different types of spherical mirror, convex and concave are taught. The various terms related with spherical mirrors like centre of curvature, radius of curvature etc, focus, pole etc are discussed Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year with ray diagrams. Uses of spherical mirror has been discussed in chapter. Mirror formula is the way to relate object distance, image distance and focal length of mirror. Magnification is the ratio of size of image by size of object.

This is related to ratio Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year of image distance and object distance. Distances are majored from pole of mirror. Sign convention is kept in mind to find relative distances of image and object. Refraction is the phenomena of bending of light when light travels from one medium to another. The phenomena of refraction can be understood easily by the concepts of refractive index and optical density. This is better explained by an example of rectangular glass slab.

This example is dealt. After that concept of Lens is explained. It is transparent medium bounded by refractive index.Ncert Solutions For 10th Science Year

Types of Lens �converging and diverging is discussed. Example of converging lens double convex lens and diverging double concave lens. Image formation and terminology is discussed for both convex and concave lens. Lens formula relates focal length of lens with image distance and object distance. Magnification Ncert Solutions For 10th Science Year is related with image and object distance. Sign convention is kept in mind. Power of lens is also discussed. Numerical based on lens formula and mirror formula are to be solved. Chapter 11 - Human Eye and colorful world Human eye, its components, are discussed.

The process of by which human eye can see objects is discussed. The ability of the eye to focus on both near and distant objects, by adjusting its focal length, is called the accommodation of the eye. The smallest distance, at which the eye can Science Ncert For Year 10th Solutions see objects clearly without strain, is called the near point of the eye or the least distance of distinct vision.

For a young adult with normal vision, it is about 25 cm. Defects of vision is discussed with their corrective measures using suitable ray diagrams. The Ncert Solutions For 10th Science Year common refractive defects of vision include myopia, hypermetropia and presbyopia. Myopia short-sightedness � the image of distant objects is focussed before the retina is corrected by using a concave lens of suitable power.

Hypermetropia far-sightedness � the image of nearby objects is focussed beyond the retina is corrected by using a convex lens of suitable power. The eye loses its power of accommodation at old age. The splitting of white light into its component colours is called dispersion. Scattering of light causes the blue colour of sky and the reddening Ncert Solutions For 10th Science Year of the Sun at sunrise and sunset.

Chapter 12 - Electricity Electricity is required for many thing around us. What is electricity? It is phenomena related to flow of charge. The concept of electric current and electric potential difference voltage is taught. Flow of electrons Ncert Solutions For 10th Science Year Ncert Year For Solutions Science 10th Ncert Solutions For 10th Science Year moving through a conductor constitutes an electric current. Conventionally, the direction of current is taken opposite to the direction of flow of electrons.

The SI unit of electric current is ampere. To set the electrons in motion in an electric circuit, we use a cell Ncert Solutions For 10th Science Year or a battery. A cell generates a potential difference across its terminals. It is measured in volts V. Resistance is a property that resists the flow of electrons in a conductor. It controls the magnitude of the current. Ohms Law, which establish relationship between potential Ncert Solutions For 10th Science Year difference and current is discussed. Concept of resistance and resistivity is studied.

Resistance is property of any conductor to resist flow of current. The resistance of a conductor depends directly on its length, inversely on its area of cross-section, and also on the material of the Ncert Solutions For 10th Science Year conductor. Resistance of conductor having unit length and cross section is defined specific resistance.

Series and parallel combination of resistors are discussed. In series current is same and in parallel potential difference is same across resistors. The unit of power is watt W. One watt of power is consumed when 1 A of current flows at a potential difference of 1 V.

The commercial unit of electrical energy is kilowatt hour kWh. Chapter 13 - Magnetic effects of Current In this chapter, relationship between magnetism and electricity is discussed. At Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Year Science For Solutions 10th first some basics of magnetism is discussed with magnetic field lines. A compass needle is a small magnet. Its one end, which points towards north, is called a north pole, and the other end, which points towards south, is called a south pole.

Magnetic Field lines are used to represent a magnetic field. A field line is the path along which a hypothetical free north pole would tend to move. The direction of the magnetic field at a point is given by the direction that a north pole placed at that Ncert Solutions For 10th Science Year point would take.

The denser magnetic field lines indicate more magnetic field strength. After that, magnetic field due to current carrying conductor is discussed. A metallic wire carrying an electric current has associated with it a magnetic field whose direction is given by right hand Ncert Solutions For 10th Science Year thumb rule. An electromagnet consists of a core of soft iron wrapped around with a coil of insulated copper wire. A current-carrying conductor when placed in a magnetic field experiences a force.

Phenomena related to this are explained. This is the basis of an electric motor. An electric motor is a device that converts electric energy into mechanical energy. Working and construction of electric motor is discussed. Electricity generation through magnet is discussed. The phenomenon of electromagnetic induction is the production of induced current in a coil placed in a Ncert Solutions For 10th Science Year region where the magnetic field changes with time.

The magnetic field may change due to a relative motion between the coil and a magnet placed near to the coil. If the coil is placed near to a current-carrying conductor, the magnetic field may change either Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year due to a change in the current through the conductor or due to the relative motion between the coil and conductor. A generator converts mechanical energy into electrical energy. It works on the basis of electromagnetic induction. Two types of generators are discussed. DC generator generates Ncert Solutions For 10th Science Year direct current as a cell.

AC generators generates Alternating Current whose direction keep on changing after a time period. Domestic circuiting is discussed.

In our houses we receive AC electric power of V with a frequency of 50 Hz. The different aspects is discussed. The concept of live wire, neutral wire and earth wire is discussed. Earth wire, insulated green which provide, passage for leakage of current.

Chapter 14 - Sources of Energy Our energy requirements increase with our standard of living. In order to fulfil our energy requirements, we Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year 10th For Ncert Science Solutions Year try to improve the efficiency of energy usage and also try and exploit new sources of energy. The chapter is all about different sources of energy. Three types of sources of energy are discussed. The first one is conventional sources of energy.

These are sources Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year of energy we keep on using from long years. It include fossil fuels, thermal power plant and hydroelectric power plant. These are discussed with advantages and disadvantages. After that, energy sources conventionally used, but improvised due to technology has been discussed.

For example, cow dung used Ncert Solutions For 10th Science Year initially had low calorific value, and combustion of it causes lot of pollution. But, with help of technology, it can converted into Bio-gas, which is an efficient and pollution free fuel. Similarly, with the help of technology, wind energy can be harnessed by placing many wind mills in a large field creating a wind farm. Charcoal obtained from wood is better fuel than wood.

All these things are discussed. The third category is Non-conventional sources of energy. In this category, we have energy sources like solar energy, in which energy Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year Ncert Solutions For 10th Science Year is generated through solar cell and solar panel, or by solar cooker. Energy from ocean can be generated through waves, tides or through temperature difference between upper and lower level of ocean.

Energy can also be obtained from earth crust, known as geo-thermal energy. Nuclear energy can generated by controlled Nuclear fission reactions. Nuclear fusion reactions generate more energy than fission but are difficult to control. All such sources of energy are discussed with their advantages and disadvantages. Chapter 15 - Our Environment The various components of an ecosystem are interdependent.