Download App

Classification of Elements and Periodicity in Properties — Chemistry STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 ScienceChemistryClassification of Elements and Periodicity in Properties5 Marks
Question
How do atomic radius vary in a period and in a group? How do you explain the variation?
✓

Answer

  1. Variation of atomic radii in a period: As we move from left to right across a period, there is regular decrease in atomic radii of representative elements. This can be explained on the basis of effective nuclear charge which increases gradually in a period, i.c, electron cloud is attracted more strongly towards nucleus as the effective nuclear charge becomes more and more along the period. The increased force of attraction brings contraction in size.

  2. Variation of atomic radii in a group: Atomic radii in a group increase as the atomic number increases. The increase in size is due to extra energy shell which outweighs the effect of increased nuclear charge.

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 "5 Marks Questions" from Classification of Elements and Periodicity in Properties→Classification of Elements and Periodicity in Properties — all question types→Chemistry STD 11 Science question papers→Rajasthan Board STD 11 Science question papers→Rajasthan Board question paper generator→

Similar questions

Following results are observed when sodium metal is irradiated with different wavelengths. Calculate (a) threshold wavelength and (b) Planck's constant.
$\lambda( nm )$500450400
$v \times 10^{-8}\left(cm s ^{-1}\right)$2.554.355.35
→
Determine the solubilities of silver chromate, barium chromate, ferric hydroxide, lead chloride and mercurous iodide at 298 K from their solubility product constants.
1. $K _{ sp }\left( Ag _2 CrO _4\right)=1.1 \times 10^{-12}$,
2. $Ksp \left( BaCrO _4\right)=1.2 \times 10^{-10}$,
3. $K _{ sp }\left[ Fe ( OH )_3\right]=1.0 \times 10^{-3}$,
Determine also the molarities of individual ions.
→
Propanal and pentan-3-one are the ozonolysis products of an alkene? What is the structural formula of the alkene?
→
A photon of wavelength 4 × 10 – 7m strikes on metal surface, the work function of the metal being 2.13eV. Calculate
  1. The energy of the photon (eV),
  2. The kinetic energy of the emission,
  3. The velocity of the photoelectron (1 eV = 1.6020 × 10 – 19J).
→
Explain the difference between reversible and irreversible processes.
→
4 In the alkane H3C-CH2-C(CH3 )2-CH2-CH(CH3)2 , identify 1°,2°,3° carbon atoms and give the number of H atoms bonded to each one of these.
→
1. Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?
2. How does
i. an electron withdrawing group (EWG) and
ii. an electron donating group (EDG) influence the acid strength of carboxylic end?
→
$K _1$ and $K _2$ for dissociation of $H _2 S$ are $4 \times 10^{-3}$ and $1 \times 10^{-5}$. Calculate sulphide ion concentration in $0.1 M H _2 S$ solution.
→
A sparingly soluble salt gets precipitated only when the product of the concentration of its ions in the solution $\left( Q _{ sp }\right)$ becomes greater than its solubility product. If the solubility of $BaSO _4$ in water is $8 \times 10^{-4} mol dm ^{-3}$, calculate its solubility in $0.01 mol dm ^{-3}$ of $H _2 SO _4$.
→
  1. $\text{Cu}|\text{Cu}^{2+}(1\text{M})||\text{Ag}^+(1\text{M})|\text{Ag}$

$\text{E}^0_\frac{\text{Cu}^{2+}}{\text{Cu}}=0.34\text{V}$

$\text{E}^0_\frac{\text{Ag}^+}{\text{Ag}}=+0.80\text{V}$

  1. Write reaction at anode and cathode.
  2. Write net cell reaction.
  3. Calculate e.m.f. of the cell.
  1. What is meant by E.M.F of cell? How is it measured?
→