Atomic structure

31.	In stable nuclei the number of protons (Z) and number of neutrons (N) are related as
	A. N > Z
	B. N <Z
	C. N = Z
	D. N = Z = 0 Option “C” is correct. Nuclei which lie on the stability line are stable nuclei. From the plot it can be seen that many of the stable nuclei have equal number of protons and neutrons. These are usually the elements in the lighter section of the periodic table. For the heavier stable nuclei the there are approximately 50% more neutrons to protons.

32.	If the number of orbitals is denoted by n, then the maximum number of electrons in an orbital will be –
	A. n
	B. n²
	C. 2n²
	D. 2n³ Option”C” is correct

33.	Electrons do not pair until the vacant orbital available for them is over, this law is called
	A. Hund’s law
	B. Pauli’s law
	C. offbau’s law
	D. heisenberg’s law Option “A” is correct. Hunds Rule of Maximum Multiplicity rule states that for a given electron configuration, the term with maximum multiplicity falls lowest in energy. According to this rule electron pairing in p, d and f orbitals cannot occur until each orbital of a given subshell contains one electron each or is singly occupied.

34.	Who propounded the principle of uncertainty?
	A. Einstein
	B. Heisenberg
	C. Rutherford
	D. Paulie has Option “B” is correct> Uncertainty principle, also called Heisenberg uncertainty principle or indeterminacy principle, statement, articulated (1927) by the German physicist Werner Heisenberg, that the position and the velocity of an object cannot both be measured exactly, at the same time, even in theory.

35.	The position and velocity of a small particle like electron cannot be simultaneously determined” This statement is.
	A. Heisenberg’s uncertainty principle
	B. Pauli’s exclusion principle
	C. Aufbau’s principle
	D. De Broglie hypothesis of wave nature of electron Option “A” is correct. Uncertainty principle, also called Heisenberg uncertainty principle or indeterminacy principle, statement, articulated (1927) by the German physicist Werner Heisenberg, that the position and the velocity of an object cannot both be measured exactly, at the same time, even in theory.

36.	With the help of which particles did Rutherford discover the nucleus?
	A. α particle
	B. β particle
	C. γ particle
	D. X particles Option “A” is correct. Rutherford directed beams of alpha particles at thin gold foil to test this model and noted how the alpha particles scattered from the foil. In the experiment, Rutherford showed us that the atom was mainly empty space with the nucleus at the centre and electrons revolving around it.

37.	Who discovered the charge of the electron?
	A. Rutherford
	B. Thomson
	C. Chadwick
	D. Millikan Option “D” is correct. Sir J. J. Thomson discovered electron but he could only deduce the charge to mass ration but Robert Milikan through his oil drop experiment found the value of charge on electron./bg_collapse]

38.	Relative charge on electron is :
	A. −1
	B. +1
	C. 0
	D. −2 Option “A” is correct. Electron is a negatively charged particle having relative charge −1.

39.	Chemical nature of an element depends on which of the followings?
	A. On proton
	B. On charge
	C. On valence electron
	D. None of the option is correct. Option “C” is correct.

40.	The chemical properties of an element depend upon ________.
	A. The number of isotopes of the element
	B. The mass number of the element
	C. The total number of neutrons in the element
	D. The number of electrons in the outermost shell of the element Option “D” is correct. Chemical properties of an element depend on the number and the configuration of their valence electrons. According to this, all the elements are sorted into 4 blocks: s, p, d, f elements. Valence Electron is the outer shell electron that is associated with an atom.

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