Wednesday, 7 April 2021

CBSE Class 10 - Chemistry - Periodic Classification Of Elements (Very Short Answer Based Questions)(#class10Chemistry)(#cbsenotes)(#eduvictors)

Class 10 - Chemistry - Periodic Classification Of Elements (Very Short Answer Based Questions)

CBSE Class 10 - Chemistry - Periodic Classification Of Elements (Very Short Answer Based Questions)(#class10Chemistry)(#cbsenotes)(#eduvictors)


Q1: What is the basis of classification of elements in the modern periodic table?

Answer: Atomic number


Q2: The Law of Octaves was applicable only upto which element?


Answer: Calcium


Q3: Which important property did Mendleev use to classify the elements in the periodic Table?

Answer: He used atomic masses of elements in classifying elements.



Q4: What were the limitations of Dobereiner’s classification?

Answer: All known elements could not be classified into groups of triads on the basis of their properties


Q5: Besides gallium, which other elements have since been discovered that were left by Mendeleev in his Periodic Table? (any two)

Answer:  Scandium and germanium


Q6: Why do you think the noble gases are placed in a separate group?

Answer: Noble gases are inert elements. Their properties are different from the all other elements. Therefore, the noble gases are placed in a separate group.


Q7: Define metallic character.

Answer: Metallic character means the tendency of an atom to lose electrons.


Q8: Name three elements that have a single electron in their outermost shells.

Answer: Lithium (Li), sodium (Na), and potassium (K) have a single electron in their outermost shells.


Q9: Name two elements that have two electrons in their outermost shells.

Answer: Magnesium (Mg) and calcium (Ca) have two electrons in their outermost shells.


Q10: Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?

Answer: Both helium (He) and neon (Ne) have filled outermost shells. Helium has a duplet in its K shell, while neon has an octet in its L shell.


Q11: In the Modern Periodic Table, which are the metals among the first ten elements?

Answer: Among the first ten elements, lithium (Li) and beryllium (Be) are metals.


Q12(MCQ): Element X forms a chloride with the formula XCl2, which is a solid with a high melting point. X would most likely be in the same group of the Periodic Table as
(a) Na
(b) Mg
(c) Al
(d) Si

Answer: X would most likely be in the same group of the Periodic Table as magnesium (Mg).


Q13: How many rows and columns are there in modern periodic table ?

Answer: The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups


Q14: An atom has electronic configuration 2, 8, 7. What is the atomic number of this element?

Answer: The atomic number of this element is 17.


Q15: Name any limitations of modern periodic table.

Answer: Position of Hydrogen


Q16: In modern periodic table, when we move from top to bottom in a group, the Metallic Character of elements __________.

Answer: increases


Q17(MCQ): Why are the elements lithium, sodium and potassium called alkali metals ?
(a) Because they reacts with water to form alkali
(b) Because they form acidic oxides
(c) Because they are present in first group
(d) Because they are less reactive in nature

Answer: (a) Because they reacts with water to form alkali


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