N.C.E.R.T. Simplified

Q. Which non-metal exists in liquid state? A. Bromine Q. What is a covalent bond? A. A covalent bond is a bond formed by sharing of electrons between two atoms to get a stable electron arrangement. e.g. O₂, H₂O, C₂H₄ etc. Q. What type of bonds are present in hydrogen chloride and oxygen? A. Covalent bonds   Q. What is an ionic bond? A. An ionic bond is a bond formed by the transfer of electrons from one atom to another. e.g. NaCl, FeSO₄, MgCl₂ etc. Q. a) What are noble gases? What is the characteristic of the electronic configuration of noble gases? b) What is the cause of chemical bonding (/combination) of atoms of elements? A. a)   The elements present in the group 18 of the periodic table are known as noble gases. These are the elements which are unreactive and do not react with other elements to form compounds.  The characteristic of electronic configuration of noble gases is that their octet (/duplet) is completely filled i.e. they have 8 ...

Q. What are social divisions of USA? A.  The social divisions in the USA are the differences between the Blacks and Whites. In USA, the Blacks tend to be poor, homeless and discriminated against. Q. Define the term homogenous society? A. A homogenous society is a society that has similar kinds of people, especially where there are no ethnic differences. Q. Does every social difference lead to social division? Explain. A.  ・No, social divisions are created when some social difference overlaps with other differences e.g. Dalits in our country tend t be poor and landless, and often face discrimination and injustice. ・A social division is created in a situation when one kind of social difference becomes more important than the other, and the people start feeling that they belong to different communities. ・Every social difference does not lead to social division. Social differences divide people from one another but they also unite very different people. Peopl...

Q. What is the magnetic effect of electric current? A.  Magnetic effect of electric current means that an electric current flowing through a conductor produces a magnetic field around it. Q. What is a magnet? A.  A magnet is an object which attracts iron, steel, nickel, and cobalt.   Q. What are the north and south poles of a magnet? A.  The end of a freely suspended (/pivoted) magnet which points towards the north direction is called the north pole of the magnet. The end of a freely pivoted magnet which points towards the south direction is called the south pole of a magnet. Q. Write a few uses of magnets. A.  i) Magnets are used in electronic goods like radios, televisions, speakers, refrigerators, audio and video cassette tapes, hard discs, computers, toys etc. ii) Magnets are also used in making electric generators and electric motors. iii) Magnets are used in the working of MRI (Magnetic Resonance  Image ) technique which is used...

Ch.3 Metals And Non-metals Extra Questions Ch.8 Periodic Classifications Extra Questions

Ch.1 Power Sharing Extra Questions Ch. 2 Federalism Extra Questions Ch.3 Democracy And Diversity Extra Questions Ch. 4 Gender, Religion and Caste Ch. 6 Political Parties Extra Questions Ch. 7 Outcomes of Democracy Ch. 8 Challenges to Democracy

Q. Write 3 features of Mendeleev's periodic table. A. ・Elements are arranged according to their increasing atomic masses. ・There are 6 periods (horizontal rows) and 8 groups (vertical columns). ・Periods 4, 5 and 6 are divided into 2 halves. Q. Which physical and chemical properties of the elements were used by Mendeleev in creating his periodic table? List two observations which posed a challenge to Mendeleev's periodic law. A.  Physical property used by Mendeleev was the atomic masses of elements and the chemical property used by him was the similar formulae of their oxides and hydrides. 2 challenging observations: i) The position of isotopes: Isotopes are the atoms of same elements with different atomic masses and hence would be provided with different spaces in Mendeleev's periodic table. ii) The position of hydrogen: Hydrogen resembles both alkali metals as well as halogens but it was placed with halogens in this table. Q. How and why does the atomic si...