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Draw the structures for the following compounds. (i) Ethanoic acid (ii) Bromopentane (iii) Butanone (iv) Hexanal

Answer: The covalently bonded carbon-containing compounds called organic compounds are substantial for life on earth. The specific branch of... View Article

What will be the formula and electron dot structure of cyclopentane?

Answer: Electron dot structures or Lewis dot formula can be drawn if the molecular formula of the compound is known. It defines the nature of... View Article

What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

Answer: Carbon forms a range of substances with a number of other elements; these compounds are known as carbon compounds. Carbon forms the basic... View Article

What would be the electron dot structure of a molecule of Sulphur which is made up of eight atoms of Sulphur? (Hint – The eight atoms of Sulphur are joined together in the form of a ring).

Answer: Sulphur has an atomic number of 16 and an electronic configuration of 2,8,6. The valance electrons on the sulphur atom are six. The... View Article

State whether the following statements are true or false. (a) An electric motor converts mechanical energy into electrical energy. (b) An electric generator works on the principle of electromagnetic induction. (c) The field at the center of a long circular coil carrying current will be parallel straight lines. (d) A wire with a green insulation is usually the live wire of an electric supply.

Answer: (1) False An electric motor converts electrical energy into mechanical energy. An electric motor is a device used to convert... View Article

At the time of short circuit, the current in the circuit (1) reduces substantially. (2) does not change. (3) increases heavily. (4) vary continuously.

Answer: (3) Increases heavily A short circuit occurs when the current in the circuit rises rapidly and the electrical connection draws an... View Article

Which sources produce alternating current?

Answer: Alternating current is an electric current that periodically reverses direction in contrast to DC which flows in only one direction. The... View Article

Draw magnetic field lines around a bar magnet.

Answer: Magnetic Field is the region around a magnetic material or a moving electric charge within which the force of magnetism acts. A bar... View Article

Compare and contrast the arrangement of elements in Mendeleev’s Periodic Table and the Modern Periodic Table.

Answer: Mendeleev’s periodic table is an arrangement of elements in an increasing atomic mass order in a tablet form, such that it reflects... View Article

In the Modern Periodic Table, calcium (atomic number 20) is surrounded by elements with atomic numbers 12, 19, 21 and 38. Which of these have physical and chemical properties resembling calcium?

Answer: Calcium has an atomic number of 20, and thus has an electronic configuration, Ca (Z = 20) = 1s2 2s2 2p6 3s2 3p6 4s2 The element having... View Article

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

Answer: The electronic configuration of an element determines the number of valence electrons and the number of shells present. We can determine... View Article

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?

Answer: Atomic number of Nitrogen = 7 Electronic configuration of Nitrogen is Nitrogen (Z= 7) = 1s2 2s2 2p3 Atomic number of phosphorous = 15... View Article

What property do all elements in the same column of the Periodic Table as fluorine have in common?

Answer: Fluorine is the ninth element with a total of 9 electrons. The first two electrons will go in the 1s orbital. The next 2 electrons for F... View Article

What property do all elements in the same column of the Periodic Table as boron have in common?

Answer: Boron is a chemical element with the atomic number of five that is present in the earth’s crust. Boron is classified as a... View Article

Which element has? (a) Two shells, both of which are completely filled with electrons? (b) The electronic configuration 2, 8, 2? (c) A total of three shells, with four electrons in its valence shell? (d) A total of two shells, with three electrons in its valence shell? (e) twice as many electrons in its second shell as in its first shell?

Answer: (a) Neon has two shells which are completely filled. The elements in Group 18 of the periodic table are known as the noble gases. These... View Article

Element X forms a chloride with the formula 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) AI (d) Si

Answer: (b) Mg We can see from the formula XCl2 that one atom of X combines with two atoms of Cl. It implies that X has a valency of two. Na... View Article

Which of the following statements is not a correct statement about the trends when going from left to right across the periods of Periodic Table. (a) The elements become less metallic in nature. (b) The number of valence electrons increases. (c) The atoms lose their electrons more easily. (d) The oxides become more acidic

Answer: (c) The atoms lose their electrons more easily. Metallic character of an element is defined as the easiness of its atom in losing... View Article

By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic? Ga Ge As Se Be

Answer: Metallic character of an element is defined as the easiness of its atom in losing electrons. According to the modern periodic table, the... View Article

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

Answer: Metals are minerals or substances that form naturally below the surface of the Earth. Most metals are lustrous or shiny. Metals are... View Article

Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?

Answer: The atoms of helium and neon have their valence shell completely filled with electrons. The number of valence electron is 8. So they do... View Article

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3	4	5	6	7	8	9
10	11	12	13	14	15	16
17	18	19	20	21	22	23
24	25	26	27	28	29	30
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