ICSE class's 10 chemistry only question s of period property
Answers
Answer:
Question 1
(i) State modern periodic law.
(ii) Name the scientist who stated the law.
(iii) How many groups and periods does modern periodic table have?
Solution 1
(i) The modern periodic law states that The properties of elements are the periodic functions of their atomic number.
(ii) Henry Moseley put forward the modern periodic law.
(iii) Modern Periodic table has 7 periods and 18 groups.
Question 2
What are horizontal rows and vertical columns in a periodic table known as?
Solution 2
The horizontal rows are known as periods and vertical columns in theperiodic table are known as groups.
Question 3
Periodicity is observed due to the similar
(number of valence electrons/ atomic number/ electronic configuration)
Solution
Periodicity is observed due to the similar electronic configuration.
Question 4
How does electronic configuration in atoms change
(i) In a period from left to right?
(ii) In a group top to bottom?
Solution 4
(i) Though the number of shells remain the same, number of valence electrons increases by one, as we move across any given period from left to right.
(ii) While going from top to bottom in a group, the number of shells increases successively i.e. one by one but the number of valence electrons remains the same.
Question 5
Name 2 elements in each case:
(i) Alkali metals
(ii) Alkaline earth metals
(iii) Halogens
(iv) Inert gas
(v) Transition metals
(vi) Lanthanides
(vii) Actinides
Solution 5
(i) Sodium and Potassium
(ii) Calcium and Magnesium
(iii) Chlorine and Bromine
(iv) Neon and Argon
(v) Iron and Cobalt
(vi) Cerium and Europium
(vii) Uranium and Neptunium
Question 6
What do you understand by?
(i) Periodicity
(ii) Typical elements
(iii) Orbits
Solution 6
(i) The properties that reappear at regular intervals, or in which there is a gradual variation at regular intervals, are called periodic properties and the phenomenon is known as the periodicity of elements.
(ii) The third-period elements, Na, Mg, Al, Si, P and Cl summarize the properties of their respective groups and are called typical elements.
(iii) Elements revolve around the nucleus in certain definite circular paths called orbits or shells.
Question 7
Name 2 elements you would expect to show chemical reactions similar to calcium. What is the basis of your choice?
Solution 7
Beryllium and magnesium will show similar chemical reactions as calcium. Since these elements belong to same group 2 andalso have two electrons in their outermost shell like calcium.