Chemistry 1

Encircle the correct answer: 

(i) Which of the following lists contains only elements? 

(a) Air, water, oxygen (b) Hydrogen, oxygen, brass 

(c) Air, water, fire, earth (d) Calcium, Sulphur, carbon

(ii) The diagrams below represent particles in four substances, which box represent the particles in nitrogen. 

(iii) What is the formula mass of CuSO₄.5H₂0. (Atomic masses: Cu=63.5, S=32, O=16, H=1) 

(a) 159.5 (b) 185.5 (c) 249.5 (d) 149.5 

(iv) A compound with chemical formula Na₂CX₃ has formula mass 106amu. Atomic mass of the element X is 

(a) 106 (b) 23 (c) 12 (d) 16 

(v) How many moles of molecules are there in 16g oxygen. 

(a) 1 

(b) 0.5 

(c)0.1 

(d) 0.05 

(vi) What is the mass of 4 moles of hydrogen gas. 

(a) 8.064g 

(b) 4.032g 

(c) 1g 

(d) 1.008g

(vii) What is the mass of carbon present in 44g of carbon dioxide. 

(a) 12 g

(b) 0 g

(c) 24 g

(d) 44 g

(viii) The electron configuration of an element is 1s²2s². An atom of this element will form an ion that will have charge. 

(a) +1

(b) +2

(c) +3

(d) -1 

(ix) Which term is the same for one mole of oxygen and one mole of water? 

(a) volume

(b) mass

(c) atoms

(c) molecules 

(x) If one mole of carbon contains x atoms, what is the number of atoms contained in 12g of Mg. 

(a) x

(b) 0.5x

(c) 2x

(d) 1.5x 

Unit-2 Structure of an tom:

(i) According to Bohr atomic model: 

(a) Each orbit has fixed energy, so each orbit is called sub-energy level.

(b) The energy of the electron is inversely proportional to its distance from the nucleus.

(c) Light is absorbed when an electron jumps a lower energy orbit.

(d) The further the electron is from the nucleus, the more energy it has.

(ii) Chlorine has two isotopes, both of which have 

(a) same mass number.

(b) same number of neutrons.

(c) different number of protons.

(d) same number of electrons.

(iii) Number of neutrons in `\ _{11}^{27}M`(²⁷M₁₁ are 

(a) 13

(b) 14

(c) 27

(d) 15

(iv) Which isotope is commonly used to irradiate cancer cells? 

(a) lodine-123

(b) Carbon-14

(c) Cobalt-60

(d) lodine-131

(v) M shell has sub-shells: 

(a) 1s, 2

(b) 2s, 2p

(c) 3s, 3p, 3d

(d) 1s, 2s, 3s

(vi) A sub-shell that can accommodate 6 electrons is 

(a) s

(b) d

(c) p

(d) f

(vii) Na has electronic configuration: 

(a) 1s² 2s² 3s¹

(b) 1s² 2s² 2p⁷

(c) 1s² 2s² 2p⁵ 3s²

(d) 1s² 2s² 2p⁶ 3s¹

(viii) Rutherford used particles in his experiments. 

(a) He atoms

(b) He⁺

(c) He⁺²

(d) He⁻²

(ix) Which of the following statement is not correct about isotopes? 

(a) they have same atomic number

(b) they have same number of protons

(c) they have same chemical properties

(d) they have same physical properties 

(x) Which isotope is used in nuclear reactors? 

(a) U-234

(b) U-238

(c) U-235

(d) All of these

Unit-3: Periodic Table and Periodicity Properties 

(i) Number of periods in the periodic table are: 

(a) 8

(b) 7

(c) 16

(d) 5

(ii) Which of the following groups contain alkaline earth metals? 

(a) 1A

(b) A

(c) VIIA

(d) VIIIA

(iii) Which of the following elements belongs to VIIIA? 

(a) Na

(b) Mg

(c) B

(d) Xe 

(iv) Main group elements are arranged in groups. 

(a) 6

(b) 7

(c) 8

(d) 10

(v) Period number of `\ _{13}^{27}Al`(²⁷Al₁₃): 

(a) 1

(b) 2

(C) 3

(d) 4

(vi) Valence shell electronic configuration of an element M (atomic no. 14) is: 

(a) 2s² 2p¹

(b) 2s² 2p²

(c) 2s² 2p³

(d) 3s² 3p²

(vii) Which of the following elements you expect to have greater shielding effect? 

(a) Li

(b) Na

(c) K

(d) Rb 

(viii) As you move from right to left across a period, which of the following does not increase:

(a) electron affinity

(b) ionization energy

(c) nuclear charge

(c) shielding effect

(ix) All the elements of Group IIA are less reactive than alkali metals. This is because these elements have:

(a) high ionization energies

(b) relatively greater atomic sizes

(c) similar electronic configuration

(d) decreased nuclear charge

Unit-4: Structure of Molecules

(i) Which of the following atoms will form an ion of charge -2? 

(a) Atomic No.=12, Mass No.=24

(b) Atomic No.=14, Mass No.=28

(c) Atomic No.=8, Mass No.=8

(d) Atomic No.=10, Mass No.=20

(ii) Which of the following atoms will not form cation or anion. 

(a) A (Atomic No. 16)

(b) B (Atomic No. 17)

(c) C (Atomic No. 18)

(d) D (Atomic No. 19)

 

(iii) Which of the following atoms will form cation. 

(a) Atomic No. 20

(b) Atomic No. 18

(c) Atomic No. 17

(d) Atomic No. 15

(iv) Which of the following atoms obey duplet rule? 

(a) O₂

(b) H₂

(c) F₂

(d) N₂

(v) Silicon belongs to Group IVA. It has___ electrons in the valence shell 

(a) 2

(b) 3

(C) 4

(d) 6

(vi) Phosphorus belongs to third period of Group VA. How many electrons it need to complete its valance shell

(a) 2

(b) 3

(C) 4

(d) 5

(vii) in the formation of AlF₃, aluminum atom loses ___ electrons

(a) 1

(b) 2

(C) 3

(d) 4

(viii) Which of the following is not true about the formation of Na₂S: 

(a) Each sodium atom loses one electron

(b) Sodium forms cation

(c) sulphur forms anion

(d) Each sulphur atom gains one electron 

(ix) Identify the covalent compound 

(a) NaCl

(b) Mgo

(c) H₂0

(d) KF

Unit-5: Physical State of Matter

(1) Which statement about the particles of a solid is not correct? 

(a) They move at great speeds

(b) They are arranged in regular patterns.

(c)There is very little space between the particles.

(d) The forces of attraction between the particles are strong. 

(ii) The boiling points of some elements are given below: 

(a) Argon -186°C

(b) Nitrogen –

(c) Oxygen -183°C

(d) Xenon 

A mixture of the above gases at -210°C was heated by 20°C. Which of the element will still be in the liquid state? 

(a) Oxygen only

(b) Argon, oxygen and xenon

(c) Argon, nitrogen and xenon

(d) Xenon only

(e) Oxygen and Xenon

The following table shows the melting and boiling points of four substances. Which substance is a solid at room temperature? 

(iv) in which of the following processes speed of the particles decreases? 

(a) melting

(b) boiling

(d) condensation

(c) sublimation

(e) evaporation

(v) Consider the following table: Sr. No XYXY (0°C) 1.00 273 0.0037 2 1.37 373 0.0037 3 1.73 473 0.0037 4 2.10 573 0.0037 Which of the following relationships does this table represent? (a) x x y (vi) (b) x = y (c) y (d) y Aliquid boils when its vapour pressure becomes equal to (b) 1 Pa (c) 101.325kPa xal Xa1 (a) 760 cmHg (d) 0.1atm.