Download App

Periodic Classification of Elements — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10SciencePeriodic Classification of Elements3 Marks
Question
What is a period in a periodic table? How do atomic structures (electron arrangements) change in a period with increase in atomic numbers from left to right?
✓

Answer

The horizontal rows of elements in a periodic table are called periods. As we move from left to right in a period, the atomic number of elements increases which means that the no. of protons and electrons in the atom increases. Due to large positive charge on the nucleus, the electrons are pulled in more close to the nucleus and the size of the atom decreases.

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 "[3 Mark Questions]" 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

What physical and chemical properties of elements were used by Mendeleev in creating his periodic table? List two observations which posed a challenge to Mendeleev’ s Periodic Law.
→
In one of his experiments with pea plants Mendel observed that when a pure tall pea plant is crossed with a pure dwarf pea plant, in the first generation, $F_1$ only tall plants appear.
  1. What happens to the traits of the dwarf plants in this case?
  2. When the $F_1$ generation plants were self-fertilised, he observed that in the plants of second generation, $F_2$ both tall plants and dwarf plants were present. Why it happened? Explain briefly.
→
A student claims that because of atmospheric refraction, the sun can be seen after it has set, and the day is, therefore, longer than if the earth had no atmosphere.
  1. What does the student mean by saying that the sun can be seen after it has set?
  2. Do you think that the students conclusion is correct?
→
An erect image 2.0cm high is formed 12cm from a lens, the object being 0.5cm high. Find the focal length of the lens.
→
How can ethanol and ethanoic acid be differentiated on the basis of their physical and chemical properties?
→
An object is 2m from a lens which forms an erect image one-fourth (exactly) the size of the object. Determine the focal length of the lens. What type of lens is this?
→
  1. Name a metal for each case:
  1. It does not react with cold as well as hot water but reacts with steam.
  2. It does not react with any physical state of water?
  1. When calcium metal is added to water, the gas evolved does not catch fire but the same gas evolved on adding sodium metal to water catches fire. Why is it so?
→
$a.$ Two electric lamps rated $100 W,220 V$ and $60 W,220 V$ are connected in parallel to electric mains supply. Calculate the current drawn from the mains if the supply voltage is $220 V?$
$b.$ A lamp consumes $50 W$ and is lighted $2 h$ daily in month of April. How many units of electric energy is consumed ?
→
An aldehyde as well as a ketone can be represented by the same molecular formula, say $C _3 H _2 O$. Write their structure and them. State the relation between the two in the language of science.
→
A population of red beetles lives in green bushes in a garden. Once during the process of breeding, a green beetle is produced.
  1. State whether the change in colour of beetle is a process of evolution or not.
  2. Can the new colour of green beetle be passed on to its next generations?
  3. What will be the advantage (if any) of the green colour to the beetle?
  4. State whether the production of green colour involved a change in genetic material or not.
→