Practice Chemistry basic - general science mcq Online Quiz (set-1) For All Competitive Exams

Q-1)   What is the mass number of an element, the atom of which contains two protons, two neutrons and two electrons?

(a)

(b)

(c)

(d)


Q-2)   Which is the symbol of the element tungsten?

(a)

(b)

(c)

(d)


Q-3)   Valency of Cr in CrP$O_4$ is

(a)

(b)

(c)

(d)


Q-4)   What is the mass (in grams) of 3 moles of N?

(a)

(b)

(c)

(d)


Q-5)   The correct symbol for silver is

(a)

(b)

(c)

(d)


Q-6)   In atom, neutron was discovered by

(a)

(b)

(c)

(d)


Q-7)   In which one of the following is the valence electronic configuration, ns2np3 found ?

(a)

(b)

(c)

(d)


Q-8)   By whom was neutron discovered?

(a)

(b)

(c)

(d)


Q-9)   Which of the following has a charge of +1 and a mass of 1 amu ?

(a)

(b)

(c)

(d)


Q-10)   Which of the following have equal number of neutrons and protons?

(a)

(b)

(c)

(d)

Explanation:

In 1H2 – no. of p = 1 and no. of n = 2 – 1 = 1


Q-11)   Which of the following are the constituents of matter?
  1. Atoms
  2. Molecules
  3. Solid

(a)

(b)

(c)

(d)


Q-12)   Which of the following pairs is/are correctly matched?
  1. Isotopes : Atoms with same atomic number but different atomic mass
  2. Isobars : Atoms with same number of neutrons but different atomic number
  3. Isotones : Atoms with same mass number but different atomic number
Select the correct answer using the code given below : Code :

(a)

(b)

(c)

(d)


Q-13)   The atomic number of an element is 11 and its mass number is 23. The correct order representing the number of electrons, protons and neutrons respectively in this atom is

(a)

(b)

(c)

(d)

Explanation:

no. of proton = At no.= number of e = 11 no. of p + no. of n = Atomic mass

∴ no. of n = 13 – 11 = 12


Q-14)   Which of the following pairs are isotopes?

(a)

(b)

(c)

(d)


Q-15)   Age of fossil may be found out by determining the ratio of two isotopes of carbon. The isotopes are

(a)

(b)

(c)

(d)


Q-16)   A single type of atom is found in

(a)

(b)

(c)

(d)


Q-17)   The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. The illustrate the law of

(a)

(b)

(c)

(d)

Explanation:

Constant proportions according to which “a pure chemical compound always contains same elements combined together in the same definite proportion of weight.”


Q-18)   Constituents of atomic nucleus are

(a)

(b)

(c)

(d)


Q-19)   The isotopes of an element have

(a)

(b)

(c)

(d)

Explanation:

Isotopes have a same atomic number but a different mass numbers.

e.g., 17Cl35 and 17Cl36 .


Q-20)   Dalton's atomic theory successfully explained
  1. Law of conservation of mass
  2. Law of constant composition
  3. Law of radioactivity
  4. Law of multiple proportions

(a)

(b)

(c)

(d)

Explanation: