Which of the following methods is NOT used for the separation of mixtures?
Chromatography
Crystallization
Distillation
Electrolysis
Correct answer is D
Uses of electrolysis:
i and ii only
ii and iv only
iii and iv
i, ii, iii and iv
Correct answer is B
The method of collecting a gas produced by a chemical reaction will depend on its solubility and its density.
The number of electrons in the 3d orbital of \(_24\)Cr is
2
3
4
5
Correct answer is D
Its electronic configuration in ground state is 1s2 2s2 2p6 3s2 3p6 4s1 3d5.
The atoms of \(^{64}_{29}\)Cu and \(^{65}_{30}\)Zn have the same number of?
nucleon
electrons
neutrons
protons
Correct answer is C
The atomic mass is written as superscript = proton number + neutron number
- Atomic mass of Cu is 64 = 29 + 35
- Atomic mass of Zn is 65 = 30 + 35
Proton number is written as subscript
One of the deductions from Rutherford's alpha particle scattering experiment is that?
electrons are negatively charged
electrons have a negligible mass
nuclei of atoms are positively charged
protons are positively charged
Correct answer is C
The model of an atom put forward by Ernest Rutherford in 1911 on the basis of experiments on the scattering of alpha particles. The model consisted of a very dense positively charged nucleus, with electrons orbiting round the nucleus.