Download App

Periodic Classification of Elements — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10SciencePeriodic Classification of Elements1 Mark
MCQ
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Number of valence electrons decreases down the group.
Reason : Number of valence electrons increases when we move left to right in a period.
  • A
    Both $A$ and $R$ are true, and $R$ is correct explanation of the assertion.
  • B
    Both $A$ and $R$ are true, but $R$ is not the correct explanation of the assertion.
  • C
    $A$ is true, but $R$ is false.
  • ✓
    $A$ is false, but $R$ is true.
✓

Answer

Correct option: D.
$A$ is false, but $R$ is true.
Number of valence electrons remains same in a group.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Assertion - Reasoning (1 Marks)" from Periodic Classification of Elements→Periodic Classification of Elements — all question types→Science STD 10 question papers→CBSE Board STD 10 question papers→CBSE Board question paper generator→

Similar questions

In the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as :
Assertion : Fuse wire must have high resistance and low melting point.
Reason : Fuse is used to protect the circuit.
 
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : A convex lens is made of two different materials. A point object is placed on the principal axis. The number of images formed by the lens will be two.
Reason : The image formed by convex lens is always virtual.
→
In the following questions, a statement of Assertion is given by the corresponding statement of Reason. Of the statements, mark the correct answer as :
Assertion : $\text{ENT}$ specialist use a concave mirror as a head mirror to concentrate light on the body parts like eye, ear, nose etc.
Reason : A concave mirror is more effective and easily available.
→
For question two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : $\ce{Cl}$ is a stronger acid than acetic acid.
Reason : On dissociation $,\ce{HCl}$ yields lesser hydrogen ions for the same concentration as compared to acetic acid.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Selfing of a plant for several generations helps plant breeders to obtain pure breeding varieties.
Reason : Pure breeding plants are heterozygous for many traits.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : A food chain can have a maximum of three trophic levels.
Reason : Energy available at each trophic level keeps on decreasing as we move higher up the food chain.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Down the group, atomic radius increases.
Reason : Electrons are added in new shell.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R)$. Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : A voltmeter and ammeter can be used together to measure resistance, but not power.
Reason : Power is proportional to voltage and current.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given below :
Assertion : Ionic compounds have high melting and boiling points.
Reason : A large amount of energy is required to break the strong inter $-$ ionic attraction in ionic compounds.
→
For two statements are given $-$ one labelled Assertion $(A)$ and the other labelled Reason $(R).$ Select the correct answer to these questions from the codes $\ce{(a), (b), (c)}$ and $(d)$ as given belown :
Assertion : If mother has two dominant alleles for black hair and father has two recessive alleles for blonde hair then their child will inherit one dominant allele from mother and one recessive allele from father and will have black hair.
Reason : Progeny inherits one genes for each trait from its parents, but the trait shown by progeny depends on inherited alleles.
→