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The atomic number of elements A, B, C, D and E are given below.
From the above table, answer the following questions.
(i) Which two elements are chemically similar?
(ii) Which element is an innert gas?
(iii) Which element belongs to 3rd period of periodic table?
(iv) Which element among these is a non-metal?
The position of five elements in the periodic table are shown below:
What are the number of valence electrons in B?
Identify the element(s) which
(i) will have the smallest atomic radius?
(ii) will be the most metallic?
(iii) will form basic oxide?
(iv) will show valency three?
(v) will show greatest tendency to gain electron?
A non-metal A which is the largest constituent of air combines with hydrogen on heating in the presence of Fe (as catalyst) and forms a gas
B. When this gas B is treated with H2SO4, compound C is formed which is broadly used as chemical fertiliser.
(i) Identify A, B and C.
(ii) Locate the position of A in the modern periodic table.
(iii) Which elements are present before and after the element A?
(iv) Write the electronic configuration of element A.
A teacher of Xth class, during teaching explains the importance of the music in our daily life. She was telling to her students that in the Indian system of music, there are seven musical notes in a scale sa, re, ga, ma, pa, da, ni. And in the west notations used are do, re, mi, fa, so, la, ti. The notes in a scale are separated by whole frequency intervals of tones. Every eighth note is similar to the first one and it is first note of next scale. A musician use these notes for composing music of a song.
Read the above passage carefully and answer the following questions accordingly.
(i) Is the situation discussed above is similar to something in chemistry? Explain.
(ii) What are the limitations of the above principle in case of chemistry?
(iii) What are the values you will infer from above passage?
Every school has assembly Students stand in rows which should be straight, horizontally as well vertical. Each class stands in a single line, with schools. Each class has a name, e.g. class 1, 2, 3... etc. In general, height of students of class 1st is smallest and 12th is biggest. Everyone sings the prayer at the same time.
Read the above passage carefully and answer the following questions given below.
(i) Do you find similarity between rows of assembly with periodic table? Explain two points.
(ii) How can you compare qualities of students with elements of periodic table?
(iii) What values are inculcated during assembly of school?
An element X combines with hydrogen to form a compound XH3. The element Xis placed on the right side of the periodic table. Which of the following statement is correct for element X?
I. Has two valence electrons.
II. Is a metal and is solid.
III. Is a non-metal and is a gas.
IV. Has five valence electrons.
V. XH3 reacts with water to forma basic compound.
Listed below are the locations of certain elements in groups and periods of the periodic table. Arrange these elements in the expected order of increasing non-metallic character:
I. Element in the fourth period and group IV A
II. Element in the third period and group VI A
III. Element in the fourth period and group VI A
IV. Element in the six period and group III A
V. Element in the second period and group VII A
The correct order is: