Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : According to Mendeleev, the properties of elements are a periodic function of their atomic masses.
Reason : Atomic number is equal to the number of protons.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Nitrogen has higher ionization energy than that of oxygen.
Reason : Nitrogen has a smaller atomic size than that of oxygen.
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Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Be, Mg and Ca can be classified as Dobereiner’s triads.
Reason : Atomic mass of Mg is approximately the average of the sum of atomic masses of Be and Ca.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Boron has a smaller first ionisation enthalpy than beryllium.
Reason : The penetration of a 2s electron to the nucleus is more than the 2p electron hence 2p electron is more shielded by the inner core of electrons than the 2s electrons.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Group 1 (1s) elements are known as the alkali elements.
Reason : s-orbital can accommodate only two electrons.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : In triad, the three elements have the same gaps of atomic masses.
Reason : Elements in a triad have similar properties
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Mendeleev’s arranged elements in horizontal rows and vertical columns.
Reason : Mendeleev’s ignored the order of atomic weight thinking that the atomic measurements might be incorrect
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Fluorine has greater atomic radius than nitrogen.
Reason : Atomic radius decreases along a period.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Smaller the size of an atom, greater is the electronegativity.
Reason : Electronegativity refers to the tendency of atom to share electrons with other atom
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Elements in the same vertical column have similar properties.
Reason : Elements have periodic dependence upon the atomic number.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : Noble gases are highly reactive.
Reason : Noble gases have stable closed shell electronic configuration.
Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion : The highest I.E. in a period is shown by noble gas.
Reason : Noble gases are at the extreme right of the period.