UPSC Chemistry-Atoms, Molecules and Nuclear Chemistry Set 1

1/12th mass of C-12 atoms ✘ Mass of C-12 atom ✘ Mass of O-16 atom ✘ Mass of Hydrogen molecule ✔

Ta ✘ Tc ✘ W ✘ V ✔

14 ✘ 28 ✘ 42 ✘ 56 ✔

6.023 ✘ 6.023 ✘ 6.023 ✘ 6.023 ✔

4 ✘ 3 ✘ 2 ✘ 1 ✔

A and B only ✘ A and C only ✘ B and C only ✘ A, B and C ✔

Dalton Number ✘ Avagadro's number ✘ Atomic Number ✘ Mass Number ✔

a molecule contains 2 atoms of P and 5 atoms of O ✘ the ratio of the mass of P to the mass of O in the Molecules is 2:5 ✘ there are twice as many P atoms in the molecule as there are O atoms ✘ the ratio of the mass of P to the mass of 0 in the molecule is 5 : 2 ✔

2g hydrogen and 32g oxygen ✘ 2g hydrogen and 16g oxygen ✘ 4g hydrogen and 32g oxygen ✘ 4g hydrogen and 14g oxygen ✔

Atoms always combine to form molecules ✘ Atoms are the basic units from which molecules and ions are formed ✘ Atoms are always neutral in nature ✘ Atoms aggregate in large numbers to form the matter that we can see, feel and touch ✔