FRANK Solutions for Class 9 Chemistry Chapter 8 - The Periodic Table
Chapter 8 - The Periodic Table Exercise 132
For Example - Lithium, Sodium, Potassium
(b) What was its basis?
(c) Was the law of octaves valid beyond calcium?
(d) A and B are two elements obeying Newland's law. How many elements are there in between A and B?
(b) It is based on the notes of the musical scale.
(c) No, the law of octaves was not valid beyond calcium i.e. not valid for heavier elements having atomic no. greater than '40'.
(d) There are 6 elements in between A and B.
(i) It was the first logical attempt to classify elements on the basis of atomic masses.
(ii) Periodicity of elements was recognized for the first time.
(ii) It simplifies and systemizes the study of the properties of various elements and their compounds.
(iii) It helps to understand the relationship between the different types of elements.
(iv) It helps to understand the cause of gradual change in properties from one element to another.
Period 1 - 2
Period 2 - 8
Period 3 - 8
(a) Two alkali metals and their groups and period.
(b) Two alkaline earth metals with their groups and periods.
(c) The group to which halogens belong.
(d) Elements of groups from 3 to 12.
(e) Noble gas with duplet arrangement of electrons.
(f) A metalloid of group 14.
(g)The bond formed between the atoms of an element of group 2 and group 16.
(h)The bond formed between the atoms an element of group 14 and group 17.
(i) Pair of elements showing a diagonal relationship.
(j) A group in which all gases are present.
Lithium - First group and second period.
Sodium - First group and third period.
(b) Two alkaline earth metals with their groups and periods are-
Beryllium - Second group and Second period
Magnesium - Second group and Third period
(c) Halogens belong to Group 17.
(d) Elements of groups from 3 to 12 are called as transition elements.
(e) Helium gas has duplet arrangement of electrons.
(f) Germanium is a metalloid of group 14.
(g) The bond formed between the atoms of an element of group 2 and group 16 is called as electrovalent or ionic bond.
(h) The bond formed between the atoms an element of group 14 and group 17 is called as covalent bond.
(i) Lithium and Magnesium are the elements which are showing a diagonal relationship.
(j) In Group 18 all elements are gases.
Chapter 8 - The Periodic Table Exercise 133
(a) The name of scientist who is related to the musical notes with classification of elements is ______ and his law is known as ______.
(b) The ______ of elements was the basis of Mendeleev's classification.
(c) There are ______ groups and ______ peiods in the present form of periodic table.
(d) Elements having outermost shell incomplete are called ______.
(e) Modern periodic law is based on ______ and was proposed by ______.
(f) Periodicity is due to repetition of ______.
(g) Moving across the period non-metallic character ______.
(h) An atom of a group 2 element has ______ in its valence shell.
(i) All the elements of a period have ______ valency.
(b) atomic masses
(c) 18, 7
(e) Atomic number, Moseley
(f) similar outer electronic configuration at certain regular intervals
(h) 2 electrons
(a) Mendeleev's periodic law was based on atomic number.
(b) Zero group was not present in the Mendeleev's periodic table.
(c) Everyperiod of periodic table begins with alkali metal.
(d) Similar electronic configuration is repeated after intervals of 2, 8, 8, 18 and 32 in long form of periodic table.
(e) Non-metals form ionic bonds among themselves.
(f) In modern periodic table isotopes of an element are placed at different places.
(g) In going down the group, metallic character may increase or decrease.
(a) Write their electronic configurations.
(b) Which element is placed right to A.
(c) Which element belongs to same group.
(d) Write the formula for sulphate of C.
(e) Which has a smaller size atom C or E.
(f) Name the element placed below A.
(g) Name the first element of the group to which D belongs.
(h) Write the formula for chloride of B.
(i) Write the formula for oxide of A.
(j) Name another non-metallic element which belongs to the same period as A.
B - 2, 3
C - 2, 8, 2
D - 2, 8, 8
E - 2, 8, 8, 2
(b) B is placed right to A.
(c) C and E belongs to same group.
(d) The formula for sulphate of C is CSO4.
(e) C has a smaller size atom.
(f) Sodium is placed below A.
(g) Helium is the first element of the group to which D belongs.
(h) The formula for chloride of B is BCl3.
(i) A2O is the formula of oxide of A.
(j) Fluorine is the non-metallic element which belongs to the same period as A.
(b) Name two elements whose atomic weights were corrected on the basis of their positions in Mendeleev's periodic table.
(c) How many elements were known at the time of Mendeleev's classification of elements.
(b) Beryllium and Gold are the two elements whose atomic weights were corrected on the basis of their positions in Mendeleev's periodic table.
(c) There were 63 elements known at the time of Mendeleev's classification of elements.
Chapter 8 - The Periodic Table Exercise 134
(i) Systematic study of the element: Elements could now be studied as groups or families rather than individuals. The Mendeleev's periodic table simplified and systemized the study of the elements and their compounds.
(ii) Prediction of new elements: While arranging the elements, in increasing order of atomic mass, Mendeleev left some blanks for the elements that were not discovered at that time. Though unknown, he was able to predict their properties more or less accurately.He named 3 of such elements as eka-boron, eka-aluminium, eka-silicon. He named them, as they were below boron,aluminium and silicon in the respective sub-groups.Eka-boron was later named as scandium, eka-aluminium as gallium and eka-silicon as germanium.
(iii) Correction of atomic masses: The Mendeleev's periodic table helped in correcting the atomic masses of elements based on their position in periodic table. Example-Atomic masses of Be was corrected from 13.5 to 9.
Example - He named eka-boron, eka- aluminium and eka-silicon to some elements as they were just below boron, aluminium and silicon in the respective sub-groups. Eka-boron was later named as scandium, eka-aluminium as gallium and eka-silicon as germanium.
(i) Their octet is attained.
(ii) They are inert in nature.
The general name of such elements is noble gas or inert elements.
(b) How many periods and groups are there in the long form of the periodic table?
(c) What is the number of elements in each period?
(b) There are 7 periods and 18 groups in the long form of the periodic table.
(c) The number of elements in each period is-
(a) What is the group number of X?
(b) What is the period number of X?
(c) How many valence electrons are there in an atom of X?
(d) What is the valency of X?
(e) Is it a metal or non-metal?
(f) Name the element right and left to it.
(g) What will be the atomic number of the elements above and below it in the periodic table?
(b) The period number of X is 3.
(c) In atom of X there are 7 valence electrons.
(d) Valency of X is 1.
(e) It is non-metal.
(f) The element right to it is Argon and the element left to it is Sulphur.
(g) The atomic number of the elements above to it is 9 and below to it is 35 in the periodic table.
(b) The elements X, Y and Z belong to group 2, 14 and 16 respectively of the periodic table:
(i) Which two elements will form covalent bond?
(ii) Which two elements will form ionic bond?
(b) (i) Y and Z will form covalent bond.
(ii) X and Z will form ionic compound.
(a) How many electrons would be there in the outermost shell of the element X?
(b) To which group of the periodic table does the element X belong?
(c) Write the formula of the compound formed when X reacts with chlorine.
(b) Element X belong to second group of the periodic table.
(v) When X reacts with chlorine, the compound formed of the formula XCl2.
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